Heteroterpene compounds and use thereof for the preparation of analgesic medicaments

Abstract

The application belongs to the technical field of medicine, and relates to a heteroterpene compound and application thereof to preparation of analgesic drugs. The application provides a heteroterpene compound with a structure shown in the following formula I, formula II, formula III, formula IV or formula V, or a racemate, an enantiomer or an epimer thereof. The heteroterpene compound in the application has significant analgesic activity, is an agonist of cannabinoid receptors CB1 and CB2, and exerts analgesic effect by acting on the cannabinoid receptors.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical technology, and more specifically, relates to heteroterpenoid compounds and their application in the preparation of analgesic drugs. Background Technology

[0002] Pain is an unpleasant sensory and emotional experience caused by actual or potential tissue damage. It is a protective response of the body to noxious stimuli, and in severe cases, it can lead to physiological dysfunction and even induce shock, endangering life. Based on duration and onset time, pain can be divided into acute pain and chronic pain. Acute pain is the body's response to tissue trauma and related inflammatory processes, has survival value, and plays a role in healing. Chronic pain, on the other hand, is persistent and recurrent, leading to a series of physiological and pathological reactions, severely impacting the patient's quality of life. Currently, commonly used analgesics in clinical practice include opioids and nonsteroidal anti-inflammatory drugs (NSAIDs). Although these two classes of drugs have significant efficacy in relieving pain, they both have varying degrees of adverse reactions. For example, NSAIDs often cause gastrointestinal and cardiovascular adverse reactions, and opioids have problems with addiction and respiratory depression, severely limiting their clinical application. Therefore, there is an urgent need to develop new analgesics with high safety and few adverse reactions.

[0003] Natural products are an important source of new drug development, and discovering novel analgesic lead compounds with well-defined mechanisms of action from natural products is an effective approach. *Rhododendron dauricum* L., a plant belonging to the genus *Rhododendron* in the family Ericaceae, is a traditional Chinese medicine whose dried leaves, also known as "Manshanhong," are used to treat asthma and acute and chronic bronchitis. In recent years, scholars both domestically and internationally have studied the chemical constituents of *Rhododendron dauricum*, discovering terpenoids, flavonoids, phenylpropanoids, and phenolic acid secondary metabolites. Modern pharmacological studies have shown that *Rhododendron dauricum* possesses analgesic, antitussive, expectorant, anti-inflammatory, and antibacterial activities; however, the pharmacodynamic basis of its analgesic effect remains unclear, indicating significant potential for future development. Summary of the Invention

[0004] The purpose of this invention is to provide heteroterpenoid compounds with analgesic effects. Another purpose of this invention is to elucidate the analgesic activity and mechanism of action of heteroterpenoid compounds, so as to solve the technical problems of low safety and large adverse reactions of analgesic drugs in the prior art.

[0005] According to a first aspect of the present invention, a heteroterpene compound is provided, said heteroterpene compound being at least one of the compounds represented by formula I, formula II, formula III, formula IV or formula V;

[0006]

[0007] Wherein: R1-R6 in Formula I, R1-R4 in Formula II, R1-R5 in Formula III, R1-R3 in Formula IV, and R1-R4 in Formula V are each independently selected from hydrogen, hydroxyl, alkyl containing 1-10 carbon atoms, carboxyl, cyano, nitro, amide, halogen, benzene ring, and heterocycle.

[0008] Preferably, the heteroterpenoid compound is a racemic, enantiomer, or epimer of the compound represented by Formula I, Formula II, Formula III, Formula IV, or Formula V.

[0009] Preferably, the heteroterpenoid compound has the structural formula of formula (+)-1, formula (-)-1, or a mixture of formula (+)-1 and formula (-)-1;

[0010]

[0011] Preferably, the heteroterpenoid compound has the structural formula of formula (+)-2, formula (-)-2, or a mixture of formula (+)-2 and formula (-)-2;

[0012]

[0013] Preferably, the heteroterpenoid compound has the structural formula of formula (+)-3, formula (-)-3, or a mixture of formula (+)-3 and formula (-)-3;

[0014]

[0015] Preferably, the heteroterpenoid compound has the structural formula of formula (+)-4, formula (-)-4, or a mixture of formula (+)-4 and formula (-)-4;

[0016]

[0017] According to another aspect of the invention, the use of the said heteroterpenoid compounds in the preparation of analgesic drugs is provided.

[0018] Preferably, the heteroterpenoid compound is used to activate cannabinoid receptors.

[0019] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages:

[0020] (1) In terms of chemical structure, the compounds provided in this invention are novel compounds discovered for the first time, and compounds (+)- / (-)-1 and 2 possess two entirely new ring systems, further enriching the chemical diversity of heteroterpenoid compounds. Compound (+)- / (-)-1 is a pair of cage-like 6 / 6 / 6 / 6 / 6-fused pentacyclic heterosesquiterpene enantiomers, possessing an unprecedented 2,8-dioxapentane [8.6.2.1]3,7 .0 11,16 .0 11,19 The ring system of nonadecane. Compound (+)- / (-)-2 is a pair of cage-like 3 / 6 / 6 / 6 / 6 / 6-fused hexacyclic heterosesquiterpene enantiomers with an unprecedented 2,8,13-trioxahexacyclic [8.7.2.1]. 3,7 .0 11 ,17 .0 11,20 .0 12,14 The cyclic system of eicosane.

[0021] (2) Regarding analgesic activity, it was discovered for the first time that compounds (±)-, (+)- / (-)-1-4 and compound 5 provided in this invention exhibit significant analgesic activity against acetic acid-induced writhing in mice at doses of 1, 0.2 and 0.04 mg / kg. Furthermore, at a lower dose of 0.2 mg / kg, the analgesic activity of compound (+)- / (-)-1 was stronger than that of the positive control drug morphine (a first-line analgesic used clinically), suggesting its potential as a novel drug component or lead compound for analgesia, with broad development prospects.

[0022] (3) This invention, through reverse virtual screening and receptor blocking experiments, first discovered that compounds (+)- / (-)-1-4 and 5 exert their analgesic activity by activating cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2). The interaction sites between compounds (+)- / (-)-1-4 and 5 and CB1 and CB2 were analyzed using computer molecular docking technology, providing a theoretical basis for further design and development of novel analgesics acting on cannabinoid receptors. Attached Figure Description

[0023] Figure 1 This is the chiral resolution chromatogram of compound (±)-1-4.

[0024] Figure 2 These are the measured and calculated ECD spectra of compound (-)- / (+)-1-4.

[0025] Figure 3 This is the X-ray single-crystal diffraction pattern of compound (-)- / (+)-1.

[0026] Figure 4 This is the X-ray single-crystal diffraction pattern of compound (+)- / (-)-2.

[0027] Figure 5The figure shows the analgesic activity of compounds (±)-, (+)- / (-)-1-4 and compound 5 at doses of 1.0, 0.2 and 0.04 mg / kg in an acetic acid-induced mouse writhing model.

[0028] Figure 6 The figure shows the experimental results of cannabinoid receptor blocking of (+)- / (-)-1-4 and compound 5.

[0029] Figure 7 This is a diagram showing the molecular docking results of compound (-)-1 with CB1 and CB2.

[0030] Figure 8 This is a diagram showing the molecular docking results of compound (+)-1 with CB1 and CB2.

[0031] Figure 9 This is a diagram showing the molecular docking results of compound (+)-2 with CB1 and CB2.

[0032] Figure 10 This is a diagram showing the molecular docking results of compound (-)-2 with CB1 and CB2.

[0033] Figure 11 This is a diagram showing the molecular docking results of compound (+)-3 with CB1 and CB2.

[0034] Figure 12 This is a diagram showing the molecular docking results of compound (-)-3 with CB1 and CB2.

[0035] Figure 13 This is a diagram showing the molecular docking results of compound (+)-4 with CB1 and CB2.

[0036] Figure 14 This is a diagram showing the molecular docking results of compound (-)-4 with CB1 and CB2.

[0037] Figure 15 This is a diagram showing the molecular docking results of compound 5 with CB1 and CB2. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0039] This invention relates to analgesic compounds, their isolation and preparation methods, and applications. Specifically, it relates to the isolation and purification process, structural confirmation, chiral resolution method, analgesic activity experiment, reverse-phase virtual screening, target verification, and molecular docking of four pairs of analgesic enantiomers and their biogenic precursors.

[0040] The present invention provides heteroterpenoid compounds having the structures shown in Formula I, Formula II, Formula III, Formula IV or Formula V, or their racemic, enantiomers, epimers or mixtures thereof and pharmaceutically acceptable salts.

[0041]

[0042] R1-R6 in Formula I, R1-R4 in Formula II, R1-R5 in Formula III, R1-R3 in Formula IV, and R1-R4 in Formula V are each independently selected from hydrogen, hydroxyl, alkyl, carboxyl, cyano, nitro, amide, halogen, benzene ring, or heterocycle.

[0043] In some embodiments, the analgesic triterpenoid compounds provided by the present invention have the following structural formula:

[0044]

[0045] Compound (±)-1: (±)-rhododaurine A

[0046] Compound (-)-1: (-)-rhododaurine A

[0047] Compound (+)-1: (+)-rhododaurine A

[0048] Compound (-)-1 is the levorotatory form of the compound of Formula I (R1-R4 are all hydrogen and R5 and R6 are all hydroxyl groups); compound (+)-1 is the dextrorotatory form of the compound of Formula I (R1-R4 are all hydrogen and R5 and R6 are all hydroxyl groups); compound (±)-1 is the racemic form of the compound of Formula I (R1-R4 are all hydrogen and R5 and R6 are all hydroxyl groups). 2,8-dioxapentacyclo[8.6.2.1] 3, 7 .0 11,16 .0 11,19 nonadecane is the name given to the cyclic skeleton in the structures of compounds (-)-1 and (+)-1.

[0049]

[0050] Compound (±)-2: (±)-rhododaurine B

[0051] Compound (+)-2: (+)-rhododaurine B

[0052] Compound (-)-2: (-)-rhododaurine B

[0053] Compound (+)-2 is the dextrorotatory form of the compound shown in Formula II (R1-R4 are all hydrogen); compound (-)-2 is the levorotatory form of the compound shown in Formula II (R1-R4 are all hydrogen); compound (±)-2 is the racemic form of the compound shown in Formula II (R1-R4 are all hydrogen). 2,8,13-trioxahexacyclo[8.7.2.1] 3,7 .0 11,17 .0 11,20 .0 12,14 eicosane is the name given to the cyclic skeleton in the structures of compounds (+)-2 and (-)-2.

[0054]

[0055] Compound (±)-3: (±)-rhododaurine C

[0056] Compound (+)-3: (+)-rhododaurine C

[0057] Compound (-)-3: (-)-rhododaurine C

[0058] Compound (+)-3 is the dextrorotatory form of the compound shown in Formula III (R1, R2, R4, and R5 are all hydrogen and R3 is a hydroxyl group); compound (-)-3 is the levorotatory form of the compound shown in Formula III (R1, R2, R4, and R5 are all hydrogen and R3 is a hydroxyl group); compound (±)-3 is the racemic form of the compound shown in Formula III (R1, R2, R4, and R5 are all hydrogen and R3 is a hydroxyl group). 2-oxatricyclo[7.4.0.0] 4,9 Tetradecane is the name given to the cyclic skeleton in the structures of compounds (+)-3 and (-)-3.

[0059]

[0060] Compound (±)-4: (±)-confluentin

[0061] Compound (+)-4: (+)-confluentin

[0062] Compound (-)-4: (-)-confluentin

[0063] Compound (+)-4 is the dextrorotatory form of the compound shown in Formula IV (R1 and R2 are both hydrogen and R3 is hydroxyl); compound (-)-4 is the levorotatory form of the compound shown in Formula IV (R1 and R2 are both hydrogen and R3 is hydroxyl); compound (±)-4 is the racemic form of the compound shown in Formula IV (R1 and R2 are both hydrogen and R3 is hydroxyl).

[0064] Compound 5: grifolin

[0065] Compound 5 is the compound shown in Formula V (R1 and R2 are both hydrogen and R3 and R4 are both hydroxyl groups).

[0066] Another embodiment of the present invention provides experimental data on the analgesic activity of compounds (±)-, (+)- / (-)-1-4, and 5. The analgesic activity of compounds (±)-, (+)- / (-)-1-4, and 5 was determined by acetic acid-induced writhing in mice. The results showed that compounds (±)-, (+)- / (-)-1-4, and 5 possessed significant analgesic activity, and compound (+)- / (-)-1 at a dose of 0.2 mg / kg still exhibited significantly stronger analgesic activity than the positive control drug morphine.

[0067] In another embodiment of the invention, potential targets of compounds (+)- / (-)-1-4 and 5 were screened. Through reverse-phase virtual screening and receptor blocking experiments, compounds (+)- / (-)-1-4 and 5 were demonstrated to be agonists of cannabinoid receptor 1 and cannabinoid receptor 2.

[0068] In another embodiment of the present invention, molecular docking software such as Autodock vina and Discovery Studio was used to study the interaction modes of compounds (+)- / (-)-1-4 and 5 with cannabinoid receptor 1 (PDB ID: 5XRA) and cannabinoid receptor 2 (PDB ID: 5ZTY).

[0069] The following are specific embodiments.

[0070] Example 1

[0071] 1. Preparation and separation of compounds (±)-, (+)- / (-)-1-4 and compound 5

[0072] 6.0 kg of dried Rhododendron dauricum leaves were pulverized and soaked five times in 12 L of 95% ethanol at room temperature for three days each time. The extracts were combined and concentrated under reduced pressure to obtain a total extract (1.6 kg). The total extract was suspended in 1.6 L of water and then extracted six times with 1.6 L of petroleum ether. The petroleum ether layers were concentrated under reduced pressure to obtain the petroleum ether extract (460 g). The petroleum ether extract was mixed with 100-200 mesh silica gel and subjected to silica gel column chromatography with a petroleum ether / ethyl acetate ratio of 100:1. 1, V / V) was used as the eluent gradient. TLC analysis and combining of identical components yielded 15 sub-components AO. Component D was then subjected to reverse-phase C... 18 Silica gel column chromatography, using methanol / water (70:1) 0, V / V) gradient elution, TLC analysis and merging of identical fractions yielded 7 subfractions D1-D7; fraction D1 was subjected to normal-phase silica gel column chromatography with petroleum ether / ethyl acetate (150:1) 1, V / V gradient elution yielded 5 subfractions D1a-D1e; fraction D1e was then processed with XB-C 18 Semi-preparative high-performance liquid chromatography (HPLC) was performed on a 5 μm, 10 × 250 mm Welch column. The mobile phase was acetonitrile / water (65:35, V / V), the flow rate was 2.0 mL / min, and the detection wavelength was 210 nm. Compound (±)-2 was obtained (retention time 41.5 min, 9.0 mg, purity 0.00015%). Component E was separated by reversed-phase C... 18 Silica gel column chromatography, using methanol / water (70:1) 0, V / V) gradient elution, TLC analysis and merging of identical components yielded five subfractions E1-E5; fraction E5 was subjected to normal-phase silica gel ( (Mesh) Column chromatography, using petroleum ether / ethyl acetate (50:1) 1, V / V gradient elution yielded six subfractions E5a-E5e and compound (±)-4 (3.8 g, purity 0.063%). Fraction O was subjected to normal-phase silica gel column chromatography with petroleum ether / ethyl acetate (100:1). 1, V / V) gradient elution, TLC examination and merging of identical components yielded 14 subfractions O1-O14; component O13 was subjected to reverse-phase C 18 Silica gel column chromatography, using methanol / water (100:1) 1, V / V gradient elution yielded 13 subfractions O13a-O13m; subfraction O13d was separated by Sephadex LH20 dextran gel column chromatography and eluted with methanol to obtain subfraction O13d1; subfraction O13d1 was further separated by XB-C... 18 Semi-preparative high-performance liquid chromatography (HPLC) was performed on a 5 μm, 10 × 250 mm Welch column. The mobile phase was acetonitrile / water (89:11, V / V), the flow rate was 2.0 mL / min, and the detection wavelength was 210 nm. Compound (±)-1 was obtained (retention time 13.8 min, 3.5 mg, purity 0.0000583%). Fraction O14 was further separated by normal-phase silica gel column chromatography with petroleum ether / ethyl acetate (80:... 1, V / V gradient elution yielded 15 subfractions O14a-O14o; fraction O14a was separated by Sephadex LH20 dextran gel column chromatography and eluted with methanol to obtain 3 subfractions O14a1-O14a3; fraction O14a3 was further separated by reversed-phase C20 chromatography. 18 Silica gel column chromatography separation, using methanol / water (80:1) 1, V / V gradient elution yielded five fractions O14a3a-O14a3e and compound 5 (2.54 g, 0.042%); fraction O14a3e was then processed with XB-C 18 Semi-preparative high-performance liquid chromatography (HPLC) was performed on a chromatographic column (5 μm, 10 × 250 mm, Welch) with acetonitrile / water (89:11, V / V) as the mobile phase, a flow rate of 2.0 mL / min, and a detection wavelength of 210 nm to obtain compound (±)-3 (retention time 41.0 min, 4.9 mg, content 0.0000817%).

[0073] Compound (±)-1 was chirally resolved by semi-preparative high-performance liquid chromatography (HPLC) using a chiral Cellu-D column (5 μm, 4.6 × 250 mm, Welch). The mobile phase was n-hexane / isopropanol (93:7, V / V), the flow rate was 1.0 mL / min, and the detection wavelength was 210 nm. This yielded a pair of enantiomers in a 1:1 ratio: (-)-1 (retention time 5.743 min, 1.2 mg) and (+)-1 (retention time 7.470 min, 1.2 mg). The chiral resolution chromatogram is shown below. Figure 1 As shown in (A) of the figure. Compound (±)-2 was chirally resolved by semi-preparative high-performance liquid chromatography (HPLC) with a chiral Cellu-D column (5 μm, 4.6 × 250 mm, Welch). The mobile phase was n-hexane / isopropanol (99:1, V / V), the flow rate was 1.0 mL / min, and the detection wavelength was 210 nm. This yielded a pair of enantiomers with a peak area ratio of 1:1: (+)-2 (retention time 9.997 min, 3.4 mg) and (-)-2 (retention time 15.664 min, 3.4 mg). The chiral resolution chromatogram is shown in the figure. Figure 1 As shown in (B) of the figure. The compound (±)-3 was chirally separated by semi-preparative high-performance liquid chromatography (HPLC) equipped with a chiral Amy-DR column (5 μm, 10 × 250 mm, Welch). The mobile phase was methanol / water (89:11, V / V), the flow rate was 2.0 mL / min, and the detection wavelength was 254 nm. A pair of enantiomers in a 1:1 ratio, (-)-3 (retention time 15.973 min, 1.5 mg) and (+)-3 (retention time 18.835 min, 1.5 mg), were obtained. The chiral separation chromatogram is shown in the figure. Figure 1As shown in (C) in the figure. Compound (±)-4 was chirally separated by semi-preparative high-performance liquid chromatography (HPLC) equipped with a chiral Amy-DR column (5 μm, 10 × 250 mm, Welch). The mobile phase was acetonitrile / water (95:5, V / V), the flow rate was 2.0 mL / min, and the detection wavelength was 254 nm. A pair of enantiomers with a peak area ratio of 1.7:1, (-)-4 (retention time 20.394 min, 18.8 mg) and (+)-4 (retention time 27.237 min, 5.6 mg), were obtained. The chiral separation chromatogram is shown in the figure. Figure 1 As shown in (D) in the diagram.

[0074] 2. Structural identification and physicochemical data of compounds (±)-, (+)- / (-)-1-4 and compound 5

[0075] Combining multiple spectroscopic analysis methods (high-resolution mass spectrometry, ultraviolet spectroscopy, infrared spectroscopy, and nuclear magnetic resonance spectroscopy) and quantum chemical calculation methods ( 13 Comprehensive analysis, including C-NMR calculations and DP4+ probability analysis, determined the structures of compounds (±)-, (+)- / (-)-1-4, and compound 5. The absolute configuration of compound (+)- / (-)-1-4 was further determined by comparing measured electronic circular dichroism (ECD) with calculated ECD (e.g., ...). Figure 2 As shown), and the structures and absolute configurations of compounds (+)- / (-)-1 and (+)- / (-)-2 were verified by X-ray single-crystal diffraction (as shown). Figure 3 and Figure 4 (As shown).

[0076] (±)-Rhododaurine A (compound (±)-1): colorless needle-like crystals; melting point 181-183℃; optical rotation [α] 25 D -1 (c 0.1, methanol); UV (methanol)λ max (logε): 211(4.39)234(3.84)287(3.02)nm;Infrared (potassium bromide)ν max 3506,3435,2923,2852,1660,1616,1568,1457,1309,1259,1139,1051,990,834cm -1 High-resolution mass spectrometry m / z [M+H] + 359.2222 (Calculated value C) 22 H 31 O4,359.2222), [M+Na] + 381.2041 (Calculated value C) 22 H30 O4Na,381.2042) and [2M+Na] + 739.4156 (Calculated value C) 44 H 60 O8Na, 739.4186). 1 H and 13 CNMR spectral data are shown in Tables 1 and 2.

[0077] (-)-Rhododaurine A (compound (-)-1): colorless needle-like crystals; melting point 171-172℃; optical rotation [α] 22 D -7 (c 0.1, methanol); ECD (methanol)λ max (Δε):201(-7.26),216(+8.12)nm, such as Figure 2 As shown in (A), the measured ECD spectrum of compound (-)-1 is consistent with the calculated ECD spectrum of (2S,3R,4S,9S,10S,15R)-1, thus confirming that the absolute configuration of compound (-)-1 is 2S,3R,4S,9S,10S,15R.

[0078] (+)-Rhododaurine A (compound (+)-1): colorless needle-like crystals; melting point 175-176℃; optical rotation [α] 22 D +7 (c 0.1, methanol); ECD (methanol)λ max (Δε):202(+7.77),216(-8.75)nm, such as Figure 2 As shown in (A), the measured ECD spectrum of compound (+)-1 is consistent with the calculated ECD spectrum of (2R,3S,4R,9R,10R,15S)-1, thus confirming that the absolute configuration of compound (+)-1 is 2R,3S,4R,9R,10R,15S.

[0079] (±)-Rhododaurine B (compound (±)-2): colorless needle-like crystals; melting point 146-147℃; optical rotation [α] 25 D +1 (c 0.1, methanol); UV (methanol)λ max (logε): 214(4.70), 238(3.95), 278(3.21) nm; Infrared (potassium bromide) ν max 2977,2929,2856,1621,1588,1491,1334,1132,986,839cm -1 High-resolution mass spectrometry m / z [M+H] + 341.2112 (Calculated value C)22 H 29 O3,341.2117), [M+Na] + 363.1935 (Calculated value C) 22 H 28 O3Na, 363.1936) and [2M+Na] + 703.3967 (Calculated value C) 44 H 56 O6Na, 703.3975). 1 H and 13 The C NMR spectral data are shown in Tables 1 and 2.

[0080] (+)-Rhododaurine B (compound (+)-2): colorless needle-like crystals; melting point 149-150℃; optical rotation [α] 25 D +139 (c 0.1, methanol); ECD (methanol)λ max (Δε): 212(+12.3)nm, as Figure 2 As shown in (B), the measured ECD spectrum of compound (+)-2 is consistent with the calculated ECD spectrum of (2S,3R,4S,9R,10S,15R)-2, thus confirming that the absolute configuration of compound (+)-2 is 2S,3R,4S,9R,10S,15R.

[0081] (-)-Rhododaurine B (compound (-)-2): colorless needle-like crystals; melting point 154-155℃; optical rotation [α]. 25 D -139 (c 0.1, methanol); ECD (methanol)λ max (Δε): 212(-13.3)nm, as Figure 2 As shown in (B), the measured ECD spectrum of compound (-)-2 is consistent with the calculated ECD spectrum of (2R,3S,4R,9S,10R,15S)-2, thus confirming that the absolute configuration of compound (-)-2 is 2R,3S,4R,9S,10R,15S.

[0082] (±)-Rhododaurine C (compound (±)-3): colorless oil; optical rotation [α] 23 D 0 (c 0.1, methanol); UV (methanol)λ max (logε): 212(4.20), 230(3.80), 277(3.28) nm; Infrared (potassium bromide) ν max3443,3383,2970,2942,2886,1625,1580,1450,1378,1336,1266,1058,825cm -1 High-resolution mass spectrometry m / z [M+H] + 327.2317 (Calculated value C) 22 H 31 O2, 327.2324), [MH] + 325.2168 (Calculated value C) 22 H 29 O2,325.2168) and [2M-H] + 651.4450 (Calculated value C) 44 H 59 O4,651.4431). 1 H and 13 The C NMR spectral data are shown in Tables 1 and 2.

[0083] (+)-Rhododaurine C (compound (+)-3): colorless oil; optical rotation [α] 23 D +116 (c0.1, methanol); ECD (methanol)λ max (Δε):206(-10.00),218(+6.69)nm, such as Figure 2 As shown in (C), the measured ECD spectrum of compound (+)-3 is consistent with the calculated ECD spectrum of (2S,3R,4S)-3, confirming that the absolute configuration of compound (+)-3 is 2S,3R,4S.

[0084] (-)-Rhododaurine C (compound (-)-3): colorless oil; optical rotation [α] 23 D -116 (c0.1, methanol); ECD (methanol)λ max (Δε):207(+4.32),216(-7.70)nm, such as Figure 2 As shown in (C), the measured ECD spectrum of compound (-)-3 is consistent with the calculated ECD spectrum of (2R,3S,4R)-3, confirming that the absolute configuration of compound (-)-3 is 2R,3S,4R.

[0085] Table 1. Compounds 1-3 1 H NMR (δ) H (J in Hz) data

[0086]

[0087]

[0088] [1] Deuterated chloroform, 400MHz; [2] Deuterated pyridine, 600MHz

[0089] Compounds 1-3 in Table 2 13 C NMR data

[0090]

[0091] [1] Deuterated chloroform, 100MHz; [2] Deuterated pyridine, 125MHz

[0092] (±)-Confluentin (compound (±)-4): colorless oil; optical rotation [α] 25 D -16 (c 0.1, methanol); High-resolution mass spectrometry m / z [M+H] + 327.2324 (Calculated value C) 22 H 30 O2, 327.2324), [MH] + 325.2168 (Calculated value C) 22 H 29 O2,325.2168) and [2M-H] + 651.4450 (Calculated value C) 44 H 59 O4,651.4431); 1 ¹H NMR (400MHz, deuterated methanol) δ H :5.45(1H,d,J=10.0Hz,H-3),6.63(1H,dd,J=10.0Hz,H-4),6.08(1H,s,H-6),6.14( 1H,s,H-8),1.62(2H,m,H2-9),2.10(2H,m,H2-10),5.11,(1H,t,J=7.1Hz,H-11),1.9 4(1H,m,H2-13),2.04(1H,m,H2-14),5.07,(1H,t,J=7.1Hz,H-15),1.65(3H,s,H3-1 7),1.57(3H,s,H3-18),1.56(3H,s,H3-19),1.32(3H,s,H3-20),2.16(3H,s,H3-21); 13 C NMR (400MHz, deuterated methanol) δ C:δ79.1(C-1),127.4(C-2),118.8(C-3),108.3(C-4a),155.4(C-5),109.5 (C-6),140.5(C-7),109.4(C-8),154.2(C-8a),42.2(C-9),23.8(C-10),1 25.7(C-11),136.1(C-12),40.9(C-13),27.9(C-14),125.6(C-15),132.2 (C-16),26.0(C-17),17.9(C-18),16.2(C-19),26.7(C-20),21.9(C-21).

[0093] (+)-Confluentin (compound (+)-4): colorless oil; optical rotation [α] 22 D +116 (c 0.1, methanol); ECD (methanol)λ max (Δε):206(-10.00),218(+6.69)nm, such as Figure 2 As shown in (D), the measured ECD spectrum of compound (+)-4 is consistent with the calculated ECD spectrum of (2S)-4, confirming that the absolute configuration of compound (+)-4 is 2S.

[0094] (-)-Confluentin (compound (-)-4): colorless oil; optical rotation [α] 22 D -116 (c 0.1, methanol); ECD (methanol)λ max (Δε):207(+4.32),216(-7.70)nm, such as Figure 2 As shown in (D), the measured ECD spectrum of compound (-)-4 is consistent with the calculated ECD spectrum of (2R)-4, confirming that the absolute configuration of compound (-)-4 is 2R.

[0095] Compound 5 (grifolin): colorless oil; high-resolution mass spectrometry m / z [M+H] + 329.2480 (Calculated value C) 22 H 33 O2,329.2481); 1 ¹H NMR (400MHz, chloroform-d)δ H:6.22(2H,s,H-4,H-6),3.37(2H,d,J=7.0Hz,H2-7),5.24(1H,t,J=7.1Hz,H-8),1.94(1H ,m,H-10a),2.10(1H,m,H-10b),1.95(1H,m,H-11a),2.00(1H,m,H-11b),5.06(1H,m,H-12 ),2.05(2H,m,H2-14),2.05(2H,overlap,H2-15),5.07(1H,m,H-16),1.65(3H,s,H3-18) ,1.57(3H,br.s,H3-19),1.58(3H,br.s,H3-20),1.79(3H,s,H3-21),2.19(3H,s,H3-22); 13 C NMR (400MHz, chloroform-d)δ C :155.1(C-1,3),110.6(C-2),109.3(C-4,6),137.8(C-5),22.4(C-7),121.9(C-8),139.2(C-9),39.9(C-10),26.9(C-11),123.8(C-12) ,135.8(C-13),39.9(C-14),26.6(C-15),124.6(C-16),131.5(C-17),25.9(C-18),17.9(C-19),16.3(C-20),16.3(C-21),21.3(C-22).

[0096] Example 2

[0097] This study evaluated the analgesic activity of compounds (±)-, (+)- / (-)-1-4, and compound 5 using an acetic acid-induced writhing model in mice. Kunming mice were randomly divided into a control group, a morphine group, and a test compound group, with 10 mice in each group (half male and half female). The control group received an intraperitoneal injection of 0.1 mL / 10 g of physiological saline, the morphine group received intraperitoneal injections of 1, 0.2, or 0.04 mg / kg of morphine, and the test compound group received intraperitoneal injections of 1, 0.2, or 0.04 mg / kg of the compound in physiological saline solution. Thirty minutes after administration, each group received an intraperitoneal injection of 0.1 mL / 10 g of 0.8% acetic acid solution. The number of writhing movements within 30 minutes immediately after injection was recorded, and the writhing inhibition rate was calculated using the following formula: Writhing inhibition rate (%) = [(Number of writhing movements in the control group - Number of writhing movements in the administered group) / Number of writhing movements in the control group] × 100%.

[0098] Conclusion: The analgesic activity of compounds (±)-, (+)- / (-)-1-4 and compound 5 was evaluated as follows: Figure 5 As shown. At a dose of 1 mg / kg, all compounds except compound (-)-3 exhibited writhing inhibition rates exceeding 50%, demonstrating significant analgesic activity. Compound (+)-1 showed a writhing inhibition rate of 80.5%, stronger than the positive control drug morphine. At a dose of 0.2 mg / kg, compounds (±)-, (+)-, and (-)-1, as well as compounds 2 and 5, all exhibited writhing inhibition rates exceeding 50%, demonstrating significant analgesic activity. Compounds (+)- and (-)-1 showed writhing inhibition rates of 68.3% and 71.4%, respectively, both stronger than the positive control drug morphine. At a dose of 0.04 mg / kg, compared to the control group, compounds (±)-, (+)-, and (-)-1, 2, and compound 5 all exhibited significant analgesic activity.

[0099] Example 3

[0100] SwisstargetPrediction is an online tool that predicts the targets of active compounds based on the similarity of their two-dimensional and three-dimensional structures to known compounds. In this example, SwisstargetPrediction was used to perform reverse virtual screening on compounds (+)- / (-)-1-4 and compound 5. The structures of compounds (+)- / (-)-1-4 and compound 5 were plotted using the Marvin JavaScript window on the SwisstargetPrediction website, with human as the species source. Of the 100 predicted targets generated, the 15 with the highest probability were selected, and their relevant information was exported.

[0101] Conclusion: Among the predicted targets of compounds (+)- / (-)-1-4 and compound 5, cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2) are both highly probable (see Table 3), indicating that compounds (+)- / (-)-1-4 and compound 5 may act on CB1 and CB2.

[0102] Table 3. Target predictions for compounds (+)- / (-)-1-4 and compound 5 (first 15)

[0103]

[0104] Example 4

[0105] CB1 and CB2 both belong to G protein-coupled receptors and play important roles in the release of chemical neurotransmitters and the regulation of the immune system. Recent studies have identified CB1 and CB2 as potential targets for treating pain, obesity, inflammation, cancer, and various mental illnesses. This embodiment uses a target blocking experiment to verify whether compounds (+)- / (-)-1-4 and compound 5 act on CB1 and CB2. Kunming mice were randomly divided into a control group, a morphine group, and a test compound group, with 10 mice in each group (half male and half female). All groups received an intraperitoneal injection of the CB1 antagonist AM251 (1 mg / kg). Ten minutes later, the control group received an intraperitoneal injection of 0.1 mL / kg of physiological saline, the morphine group received an intraperitoneal injection of 1 mg / kg of morphine, and the test compound group received an intraperitoneal injection of 1 mg / kg of the compound in physiological saline solution. Thirty minutes later, each group received an intraperitoneal injection of 0.1 mL / 10 g of 0.8% acetic acid solution. Immediately after the intraperitoneal injection, the number of writhing movements in the mice within 30 minutes was recorded, and the writhing inhibition rate was calculated. The CB2 blockade experiment used the antagonist AM630 (1 mg / kg, intraperitoneal injection), and the rest of the methods were the same as above.

[0106] Conclusion: Figure 6 As shown, after administration of antagonists of CB1 and CB2, the analgesic activity of compounds (+)- / (-)-1-4 and 5 was significantly reduced, indicating that compounds (+)- / (-)-1-4 and 5 are agonists of CB1 and CB2 and exert their analgesic effect by activating cannabinoid receptors.

[0107] Example 5

[0108] In this embodiment, Autodock vina 1.2.3 was used to dock the active compound (+)- / (-)-1-4 and compound 5 with CB1 (pbd ID: 5XRA) and CB2 (pbd ID: 5ZTY), respectively. The results were analyzed using Discovery Studio 2019 software and visualized using pymol.

[0109] Conclusion: The docking results of (+)- / (-)-1-4 and 5 with CB1 and CB2 are as follows: Figure 7-15 As shown. Compound (+)-1 forms intermolecular hydrogen bonds with the Ser383 and Cys386 amino acid residues of CB1, and with the His95 and Ser285 amino acid residues of CB2. Figure 7 Compound (+)-1 forms intermolecular hydrogen bonds with the Ser383 amino acid residue of CB1 and with the Trp258 amino acid residue of CB2. Figure 8Compound (+)-2 forms intermolecular hydrogen bonds with the Ser383 amino acid residue of CB1 and with the Ser285 amino acid residue of CB2. Figure 9 Compound (-)-2 forms intermolecular hydrogen bonds with the Ser383 amino acid residue of CB1 and with the Ser285 amino acid residue of CB2. Figure 10 Compound (+)-3 forms intermolecular hydrogen bonds with the Leu193 amino acid residue of CB1, and with the Met265 and Ser285 amino acid residues of CB2. Figure 11 Compound (+)-3 forms intermolecular hydrogen bonds with the Lys192 amino acid residue of CB1 and with the His95 amino acid residue of CB2. Figure 12 Compound (+)-4 forms intermolecular hydrogen bonds with the Phe174 amino acid residue of CB1 and with the Thr114 amino acid residue of CB2. Figure 13 Compound (-)-4 forms intermolecular hydrogen bonds with the Thr197 amino acid residue of CB1 and with the Thr114 amino acid residue of CB2. Figure 14 Compound 5 forms intermolecular hydrogen bonds with the Thr197 amino acid residue of CB1 and with the Thr114 amino acid residue of CB2. Figure 15 ).

[0110] The above results suggest that compounds (+)- / (-)-1-4 and 5 may exert their activating effects by acting on amino acid residues Phe174, Lys192, Leu193, Thr197, Ser383 or Cys386 in CB1 and amino acid residues His95, Thr114, Trp258, Met265, Ser285 in CB2, providing a theoretical basis for the further design and development of novel analgesics acting on cannabinoid receptors.

[0111] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A heteroterpene compound, characterized in that, The structural formula of the heteroterpenoid compound is (+)-1, (-)-1, or a mixture of (+)-1 and (-)-1; 、 Equation (+)-1 Equation (-)-1.

2. A heteroterpene compound, characterized in that, The heteroterpenoid compounds have the structural formulas (+)-2, (-)-2, or a mixture of (+)-2 and (-)-2. 、 Equation (+)-2 Equation (-)-2.

3. The use of the heteroterpenoid compound as described in any one of claims 1-2 in the preparation of analgesic drugs.

4. The application as described in claim 3, characterized in that, The heteroterpenoids are used to activate cannabinoid receptors.

Images