Active components in selaginella tamariscina and application thereof in inhibiting alpha-glucosidase

Abstract

The application discloses active components in Selaginella lepidophylla and application of the active components in inhibition of alpha-glucosidase. The active components comprise four sesquiterpenes, three lignans and three biflavones; wherein, compound 1 is a new sesquiterpene compound, and compounds 2-10 are obtained from Selaginella lepidophylla for the first time. The compounds obtained by separation are subjected to in-vitro enzyme inhibition activity evaluation, so as to lay a scientific foundation for reasonable development and utilization of Selaginella lepidophylla plant resources. The alpha-glucosidase inhibition activity test result shows that compounds 7-10 have good alpha-glucosidase inhibition activity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of active ingredient research of plant extracts, and particularly relates to an active component in Selaginella prostrata and application thereof in inhibiting alpha-glucosidase. BACKGROUND

[0002] Selaginella prostrata is a perennial herbaceous plant of Selaginellaceae Selaginella, which is often found in stone crevices or under moss stones at an altitude of 1500-2500 meters, and is distributed in Guizhou, Yunnan and Sichuan provinces. The whole grass of Selaginella prostrata can be used for medicine, and after being dried or burned into charcoal, it is ground into powder and mixed with tea oil for external application to stop bleeding; stewed with wine for internal use, it can treat injuries, amenorrhea and blood stasis, etc. In addition, Selaginella prostrata also has high ornamental value and can be cultivated for ornamental purposes.

[0003] Selaginella plants are diverse and abundant in resources, with about 700 species in the world, mainly produced in tropical regions. Among them, there are more than 70 species in China, and they are widely distributed in various parts of the country. More than 20 species of plants such as Selaginella braunii and Selaginella moorei have been widely used as traditional folk medicines. As official medicines, Selaginella and Selaginella pulvinata have been included in the 2020 edition of Chinese Pharmacopoeia, and have the effects of removing blood stasis, stopping bleeding, promoting blood circulation and unblocking channels, which can be used for the treatment of injuries, amenorrhea, metrorrhagia, hemoptysis and metrorrhagia. Modern research shows that Selaginella plants contain flavonoids, lignans, alkynols and terpenes, etc. and have the effects of lowering blood sugar, antioxidant, anti-aging, anti-tumor, anti-inflammatory, antibacterial, etc. At present, the research on Selaginella plants at home and abroad mainly focuses on Selaginella, Selaginella sinensis and Selaginella moorei, and the research on other plants in this genus is less. Selaginella prostrata belongs to Selaginella plants, and so far there is no literature report on its chemical composition and pharmacological activity. SUMMARY

[0004] The purpose of the present application is to provide an active component in Selaginella prostrata and its application in inhibiting alpha-glucosidase.

[0005] An active component composition in Selaginella prostrata, the composition is one or several of seprostrataoid A, (3S,5R,8S)-5,8-epoxy-6-megastigmadien-3,9-diol, (-)-ludalbin, (3S,5R,6R,7E)-3,5,6-trihydroxy-7-megastigmadien-9-one, (7R,8S)-ceplignan, (2R,3S)-dihydro-2-(3',5'-dimethoxy-4'-hydroxyphenyl)-3-hydroxymethyl-7-methoxy-5-acetyl benzopyran, 5,5'-dimethoxy xanthoxyl A, strobopin, isocryptomerin and hinokiflavone.

[0006] Said seprostrataoid A, (3S, 5R, 8S)-5, 8-epoxy-6-megastigmadien-3, 9-diol, (-)-ludalactone, (3S, 5R, 6R, 7E)-3, 5, 6-trihydroxy-7-megastigm-9-one, (7R, 8S)-ceplignan, (2R, 3S)-dihydro-2-(3', 5'-dimethoxy-4'-hydroxyphenyl)-3-hydroxymethyl-7-methoxy-5-acetyl benzodioxofuran, 5, 5'-dimethoxy xanthohumol A, styraxflavone, isocryptomerin, and taxifolin.

[0007] Preferably, said composition is 5, 5'-dimethoxy xanthohumol A, styraxflavone, isocryptomerin, and taxifolin.

[0008] Application of the active components in said Selaginella tamariscina in inhibiting α-glucosidase.

[0009] Preferably, said active components are one or more of 5, 5'-dimethoxy xanthohumol A, styraxflavone, isocryptomerin, and taxifolin.

[0010] Advantages of the present application: the present application comprehensively uses silica gel, Sephadex LH-20, semi-preparative HPLC and other chromatographic separation technologies to separate 10 compounds from 95% ethanol extract of Selaginella tamariscina, and evaluates the in vitro enzyme inhibition activity of the separated compounds, so as to lay a scientific foundation for rational development and utilization of Selaginella tamariscina plant resources, and the α-glucosidase inhibition activity test results show that compounds 7-10 have good α-glucosidase inhibition activity, and IC 50 values are 72.14±2.67, 42.68±1.54, 61.26±4.32, and 55.43±2.17 μM, respectively. The 10 compounds of the present application include 4 sesquiterpenes, 3 lignans, and 3 biflavones; among them, compound 1 is a new sesquiterpene compound, and compounds 2-10 are first separated from Selaginella tamariscina. DETAILED DESCRIPTION

[0011] In order to facilitate understanding of the present application, the present application will be described more fully below. However, the present application can be realized in many different forms, and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0012] Example 1

[0013] Reagents and instruments used in this example: Bruker 400 and 600 MHz nuclear magnetic resonance spectrometer (Germany Bruker Corporation); Agilent 6545Q-TOF liquid chromatograph-mass spectrometer, Cary 3500 ultraviolet-visible spectrophotometer (USA Agilent Corporation); Tensor 37 Fourier transform infrared spectrometer (Bruker Optics Corporation); ELX-800 microplate reader (USA BioTek Corporation); Elute P3700 semi-preparative liquid chromatograph (Dalian Elute Analytical Instrument Co., Ltd.); 200-300 mesh column chromatography silica gel and silica gel GF254 thin layer plate (Qingdao Marine Chemical Co., Ltd.); RP-18 reversed-phase column chromatography silica gel and YMC-Pack Pro C18 Chromatographic column: 5 μm, 250 mm x 10 mm (Japan YMC Corporation); Sephadex LH-20 dextran gel (Germany Merck Corporation); chromatographic acetonitrile, methanol (USA Tedia Corporation); water is laboratory ultrapure water; dichloromethane, methanol and other analytical reagents are products of Xilong Chemical Co., Ltd.; α-glucosidase, 4-nitrophenyl-β-D-glucopyranoside (USA Sigma Corporation); acarbose (Shanghai Yuan Ye Biological Technology Co., Ltd.). Selaginella prostrata was collected in Yiliang County, Yunnan Province, China in July 2021, and identified by Professor Jiang Hongyu of Hunan University of Science and Technology as the whole grass of Selaginella prostrata of the family Selaginellaceae. The plant sample specimen (2021-PS-0701) was stored in the Hunan Yancon Engineering Technology Research Center.

[0014] Experimental method

[0015] Extraction and separation: 10 kg of dried whole grass of Selaginella prostrata was powdered and extracted with 95% ethanol by heating reflux for 3 times, 3 hours each time. The combined extract was concentrated to obtain 1.2 kg of crude extract. The crude extract was suspended in water and successively extracted with dichloromethane, ethyl acetate, n-butanol. The concentrated extract was obtained respectively as 148 g of dichloromethane fraction, 426 g of ethyl acetate fraction, 220 g of n-butanol fraction and 406 g of water fraction.

[0016] The ethyl acetate extract fraction was separated by silica gel column chromatography with gradient elution of dichloromethane-methanol (100:1→5:1) to give 9 fractions (E1-E9). Among them, fraction E3 was separated by Sephadex LH-20 gel column (methanol) to give 6 sub-fractions E3.1-E3.6. Sub-fraction E3.3 was separated by thin layer preparation and semi-preparative HPLC (methanol:water, 30:70, 2 mL / min) to give compound 1 (tR=36.2 min, 10.4 mg) and 4 (tR=9.9 min, 6.7 mg). Sub-fraction E3.4 was separated by silica gel column chromatography with gradient elution of dichloromethane-methanol (80:1→3:1) to give compound 2 (8.0 mg) and 3 (4.5 mg). Fraction E4 was separated by ODS column chromatography with gradient elution of methanol-water (20:80→100:0) to give 7 sub-fractions E4.1-E4.7. Sub-fraction E4.2 was separated by Sephadex LH-20 gel column (methanol) to give compound 7 (10.3 mg). Sub-fraction E4.3 was separated by Sephadex LH-20 gel column (methanol) and semi-preparative HPLC (acetonitrile:water, 25:75, 2 mL / min) to give compound 5 (tR=37.3 min, 15.7 mg) and 6 (tR=45.8 min, 9.2 mg). Fraction E6 was separated by repeated silica gel column chromatography and gel column chromatography to give compound 8 (19.8 mg), 9 (24.6 mg) and 10 (15.9 mg).

[0017] In vitro α-glucosidase inhibitory activity test: 50 μL of phosphate buffer (pH=6.8), 20 μL of sample solution (final mass concentration of 0.2, 0.1, 0.05, 0.025 mg / mL), 10 μL of α-glucosidase solution (1 U / mL) and 20 μL of p-nitrophenyl-α-D-glucopyranoside solution (2.5 mmol / L) were accurately pipetted in a 96-well plate in turn with acarbose as a positive control, and incubated at 37°C for 15 min, then 150 μL of Na2CO3 solution was added to terminate the reaction. The absorbance (A) was measured at 405 nm by a microplate reader, and the sample group and the blank group were set, and the operation was carried out in parallel for 3 times, and the average value was taken. The inhibition rate was calculated according to the formula. Inhibition rate = [1-(A sample-A sample blank) / A blank] x 100%

[0018] Compound 1: colorless oily liquid; quasi-molecular ion peak m / z 275.161 8 [M+Na] according to (+)-HR-EI-MS + (calcd for C 15 H 24 O3Na, 275.161 8) and one-dimensional nuclear magnetic data to determine its molecular formula as C 15 H 24O3, unsaturation 4; IR (KBr) v max 3 375, 2 932, 1 728, 1 612, 1 520, 1 384, 1 261, 1 227, 1 114, 1050, 973 cm –1 The above characteristic absorption peaks suggest the presence of hydroxyl and carbon-carbon double bond functional groups in the structure of the compound; the 1 H NMR spectrum (see Table 1) shows the presence of two olefinic hydrogen signals δ H 5.65 (1H, m), 5.32 (1H, br s), two oxymethine signals δ H 5.12 (1H, br s), 3.96 (1H, m), one oxymethylene signal δ H 4.15 (1H, br s), 4.13 (1H, br s), two methylene signals δ H 2.21 (1H, ddd, J = 2.0, 4.4, 12.4 Hz), 1.84 (1H, ddd, J = 2.0, 4.4, 12.4 Hz), 1.54 (1H, overlapped), 1.21 (1H, overlapped), and four methyl signals δ H 1.59 (3H, s), 1.44 (3H, s), 1.21 (3H, s), 1.15 (3H, s); 13 C NMR spectrum (see Table 1) shows that the compound has a total of 15 carbon signals, which can be assigned to four olefinic carbon signals (δ C 154.4, 138.3, 128.0, 121.2), two oxymethine carbon signals (δ C 66.2, 89.5), three methylene carbon signals (δ C 59.3, 51.0, 50.8), four methyl carbon signals (δ C 31.2, 27.5, 27.3, 12.0), and two quaternary carbon signals (δ C 89.3, 34.2). The above data suggest that compound 1 is a sesquiterpenoid compound. By comparison, it is found that the NMR data of compound 1 and (3S,5R,8S)-5,8-epoxy-6-megastigmadien-3,9-diol (2) [18,19] are relatively similar, and the main difference between the two structures is the side chain group connected to C-8. The structure of compound 1 was confirmed by 2D NMR experiments, and the results are shown in Table 2. 1 H- 1The correlation signals between H-3 / H-2, H-3 / H-4, H-7 / H-8, H-10 / H-11 in the H COSY spectrum indicated the presence of C(2)H2-C(3)H-C(4)H2, C(7)H-C(8)H, C(10)H-C(11)H2 structural units. The main 1 H- 1 H COSY, HMBC and NOESY correlations.

[0019] The correlation signals between H-11, H3-12 and C-9, C-10; H-7 and C-1, C-6; H-8 and C-7, C-9, C-10, C-12, C-15 in the HMBC spectrum confirmed the planar structure of compound 1. The relative configuration of compound 1 was determined by the NOESY spectrum, in which the correlation signals between H3-13 / H-3, H-3 / H3-15, H3-15 / H-8, H-8 / H3-12 indicated that H-3, H-8, Me-13 and Me-15 were located on the same side of the ring system. The stereochemistry of C-8 was determined as R according to the positive Cotton effect observed at 208 nm in the experimental circular dichroism spectrum

[20] , and the stereochemistry of compound 1 was finally determined as 3R, 5R, 8R, 9E. SciFinder search confirmed that compound 1 was a new sesquiterpenoid compound, and it was named as seprostrataoid A.

[0020] Table 1 Hydrogen and carbon spectral data of compound 1 (400 and 100 MHz, CD3OD)

[0021]

[0022] Compound 2: colorless oil; HR-EI-MS: m / z 227.165 0 [M+H] + (calcd for C 13 H 23 O3, 227.164 2); 1H NMR (400 MHz, CD3OD) δ: 5.75 (1H, s, H-7), 4.75 (1H, br d, J = 7.2 Hz, H-8), 4.50 (1H, m, H-3), 3.92 (1H, m, H-9), 2.60 (1H, br d, J = 14.0 Hz, H-4b), 2.04 (1H, br d, J = 14.0 Hz, H-2b), 1.99 (3H, s, H-13), 1.50 (1H, dd, J = 13.6, 3.2 Hz, H-2a), 1.42 (3H, d, J = 6.6 Hz, H-10), 1.40 (3H, s, H-11), 1.12 (3H, s, H-12); 13 CNMR (100 MHz, CD3OD) δ: 34.2 (C-1), 51.1 (C-2), 66.4 (C-3), 51.0 (C-4), 89.4 (C-5), 154.5 (C-6), 119.8 (C-7), 88.4 (C-8), 71.2 (C-9), 19.0 (C-10), 27.5 (C-11), 31.2 (C-12), 27.4 (C-13). The above data are in agreement with the literature reported, thus compound 2 was identified as (3S,5R,8S)-5,8-epoxy-6-megastigmadien-3,9-diol.

[0023] Compound 3: white powder; HR-EI-MS: m / z 197.116 9 [M+H] + (calcd for C 11 H 17 O3, 197.117 2); 1 H NMR (400 MHz, CD3OD) δ: 5.74 (1H, s, H-7), 4.22 (1H, m, H-3), 2.44 (1H, ddd, J = 13.2, 2.8, 2.4 Hz, H-4b), 1.96 (1H, ddd, J = 14.4, 2.8, 2.4 Hz, H-2b), 1.78 (3H, s, H-11), 1.76 (1H, dd, J = 13.2, 4.0 Hz, H-4a), 1.55 (1H, dd, J = 14.4, 3.6 Hz, H-2a), 1.46 (3H, s, H-10), 1.32 (3H, s, H-9); 13C NMR (100 MHz, CD3OD) δ: 37.4 (C-l), 48.0 (C-2), 67.5 (C-3), 46.5 (C-4), 89.2 (C-5), 185.9 (C-6), 113.7 (C-7), 174.5 (C-8), 31.5 (C-9), 27.0 (C-10), 27.4 (C-l l). The above data are in good agreement with the literature reported, thus compound 3 was identified as (-)-loliolide.

[0024] Compound 4: white powder; HR-EI-MS: m / z 243.159 9 [M+H] + (calcd for C 13 H 23 O4, 243.159 1); 1 H NMR (600 MHz, CD3OD) δ: 7.40 (1H, d, J = 16.2 Hz, H-7), 6.38 (1H, d, J = 16.2 Hz, H-8), 4.09 (1H, m, H-3), 2.30 (3H, s, H-10), 1.80 (1H, m, H-4β), 1.72 (1H, m, H-4α), 1.68 (1H, t, J = 12.0 Hz, H-2β), 1.25 (3H, s, H-11), 1.12 (1H, m, H-2α), 1.12 (3H, s, H-13), 0.85 (3H, s, H-12); 13 C NMR (150 MHz, CD3OD) δ: 41.2 (C-l), 46.2 (C-2), 65.0 (C-3), 45.5 (C-4), 77.7 (C-5), 80.0 (C-6), 132.2 (C-7), 152.8 (C-8), 201.2 (C-9), 26.4 (C-10), 27.5 (C-l l), 26.9 (C-12), 27.2 (C-13). The above data are in good agreement with the literature reported, thus compound 4 was identified as (3S,5R,6R,7E)-3,5,6-trihydroxy-7-megastigmen-9-one.

[0025] Compound 5: white powder; HR-EI-MS: m / z 347.113 8 [M+H] + (calcd for C 18 H 19 O7, 347.112 6); 1H NMR (400 MHz, CD3OD) δ: 7.65 (1H, br s, H-6'), 7.57 (1H, br s, H-2'), 6.98 (1H, br s, H-2), 6.86 (1H, br s, H-6), 6.79 (1H, br s, H-5), 5.62 (1H, d, J = 6.0 Hz, H-7), 3.90 (3H, s, 3'-OCH3), 3.82 (2H, m, H-9), 3.81 (3H, s, 3-OCH3), 3.58 (1H, m, H-8); 13 C NMR (100 MHz, CD3OD) δ: 124.1 (C-l'), 114.0 (C-2'), 143.9 (C-3'), 55.3 (3'-OCH3), 152.5 (C-4'), 129.0 (C-5'), 119.5 (C-6'), 169.0 (C-7'), 132.8 (C-l), 109.3 (C-2), 147.6 (C-3), 55.0 (3-OCH3), 146.5 (C-4), 114.8 (C-5), 118.5 (C-6), 88.7 (C-7), 53.1 (C-8), 63.3 (C-9). The above data are in agreement with the literature reported, thus compound 5 was identified as (7R,8S)-ceplignan.

[0026] Compound 6: pale yellow oil; HR-EI-MS: m / z 397.125 8 [M+Na] + (calcd for C 20 H 22 O7Na, 397.125 0); 1 H NMR (400 MHz, Acetone-d6) δ: 7.62 (1H, br s, H-4), 7.52 (1H, br s, H-6), 6.74 (2H, s, H-2', H-6'), 5.64 (1H, d, J = 7.2 Hz, H-2), 3.93 (2H, m, CH2OH), 3.90 (3H, s, 7-OCH3), 3.80 (6H, s, 3'-OCH3, 5'-OCH3), 3.66 (1H, m, H-3), 2.50 (3H, s, COCH3); 13C NMR (100 MHz, Acetone-d6) δ: 89.6 (C-2), 53.8 (C-3), 119.6 (C-4), 130.2 (C-5), 113.0 (C-6), 144.8 (C-7), 153.4 (C-8), 132.0 (C-9), 132.2 (C-l'), 104.2 (C-2', C-6'), 148.6 (C-3', C-5'), 136.0 (C-4'), 197.1 (COCH3), 26.4 (COCH3), 63.7 (CH2OH), 56.5 (3'-OCH3, 5'-OCH3), 56.2 (7-OCH3). The above data are in agreement with the literature reported, thus compound 6 was identified as (2R, 3S)-dihydro-2-(3', 5'-dimethoxy-4'-hydroxyphenyl)-3-hydroxymethyl-7-methoxy-5-acetylbenzopyran.

[0027] Compound 7: light yellow powder; HR-EI-MS: m / z 441.153 5 [M+Na] + (calcd for C 22 H 26 O8Na, 441.152 0); 1 H NMR (600 MHz, CDC13) δ: 7.24 (2H, d, J = 1.8 Hz, H-6, H-6'), 7.16 (2H, d, J = 1.8 Hz, H-2, H-2'), 4.75 (2H, d, J = 4.2 Hz, H-7, H-7'), 4.27 (2H, dd, J = 9.0, 7.2 Hz, H-9a, H-9'a), 3.98 (6H, s, 3-OCH3, 3'-OCH3), 3.92 (6H, s, 4-OCH3, 4'-OCH3), 3.88 (2H, dd, J = 9.0, 4.2 Hz, H-9b, H-9'b), 3.12 (2H, t, J = 4.2 Hz, H-8, H-8'); 13 C NMR (150 MHz, CDC13) δ: 132.9 (C-l, C-l'), 103.8 (C-2, C-2'), 152.5 (C-3, C-3'), 146.3 (C-4, C-4'), 149.1 (C-5, C-5'), 109.1 (C-6, C-6'), 86.1 (C-7, C-7'), 54.4 (C-8, C-8'), 71.9 (C-9, C-9'), 56.3 (3-OCH3, 3'-OCH3), 61.2 (4-OCH3, 4'-OCH3). The above data are in agreement with the literature reported, thus compound 7 was identified as 5, 5'-dimethoxyxanthohumol A.

[0028] Compound 8: yellow powder; HR-EI-MS: m / z 539.098 8[M+H] + (calcd for C 30 H 19 O 10 , 539.097 3); 1 H NMR (400 MHz, CD3OD) δ: 7.92 (1H, br s, H-2″′), 7.75 (1H, br d, J = 8.0 Hz, H-6″′), 7.42 (2H, d, J = 8.4 Hz, H-2′, H-6′), 7.05 (1H, d, J = 8.0 Hz, H-5″′), 6.68 (2H, d, J = 8.4 Hz, H-3′, H-5′), 6.52 (2H, br s, H-3, H-3″), 6.37 (1H, br s, H-8″), 6.33 (1H, s, H-6), 6.15 (1H, br s, H-6″); 13 C NMR (100 MHz, CD3OD) δ: 166.0 (C-2), 103.4 (C-3), 184.0 (C-4), 162.5 (C-5), 100.2 (C-6), 163.6 (C-7), 105.3 (C-8), 156.5 (C-9), 105.4 (C-10), 121.6 (C-1′), 129.4 (C-2′), 116.8 (C-3′), 162.9 (C-4′), 116.8 (C-5′), 129.4 (C-6′), 166.0 (C-2″), 104.1 (C-3″), 183.7 (C-4″), 162.5 (C-5″), 100.2 (C-6″), 165.9 (C-7″), 95.2 (C-8″), 159.3 (C-9″), 105.5 (C-10″), 123.2 (C-1″′), 129.0 (C-2″′), 123.2 (C-3″′), 161.0 (C-4″′), 117.4 (C-5″′), 132.8 (C-6″′). The above data are in agreement with the literature reported, thus compound 8 was identified as St. John’s wort biflavone.

[0029] Compound 9: tan powder; HR-EI-MS: m / z 553.112 2[M+H] + (calcd for C 31 H 21 O 10 , 553.113 0); 1H NMR (400 MHz, DMSO-d6) δ: 13.10 (1H, s, 5-OH), 12.90 (1H, s, 5"-OH), 10.85 (1H, s, 7"-OH), 10.42 (1H, s, 4'-OH), 8.02 (2H, d, J = 8.4 Hz, H-2"', H-6"'), 8.00 (2H, dd, J = 8.4, 3.6 Hz, H-2', H-6'), 7.12 (1H, s, H-3"), 7.04 (2H, d, J = 8.4 Hz, H-3"', H-5"'), 6.97 (2H, d, J = 8.4 Hz, H-3', H-5'), 6.94 (1H, s, H-3), 6.88 (1H, br s, H-8), 6.50 (1H, d, J = 2.0 Hz, H-8"), 6.20 (1H, d, J = 2.0 Hz, H-6"), 3.90 (3H, s, 7-OCH3); 13 C NMR (100 MHz, DMSO-d6) δ: 164.3 (C-2), 103.8 (C-3), 181.8 (C-4), 161.5 (C-5), 98.8 (C-6), 164.2 (C-7), 94.0 (C-8), 157.2 (C-9), 103.8 (C-10), 124.2 (C-l'), 128.5 (C-2', C-6'), 115.2 (C-3', C-5'), 160.4 (C-4'), 163.2 (C-2"), 102.9 (C-3"), 182.2 (C-4"), 152.5 (C-5"), 124.8 (C-6"), 158.1 (C-7"), 92.0 (C-8"), 154.1 (C-9"), 104.0 (C-10"), 121.0 (C-l"'), 128.5 (C-2"', C-6"'), 116.0 (C-3"', C-5"'), 161.5 (C-4"'), 56.8 (7-OCH3). The above data are in agreement with the reported data

[28] The reported data are basically consistent, so compound 9 is identified as isokisufolin.

[0030] Compound 10: yellowish brown powder; HR-EI-MS: m / z 539.098 4 [M+H] + (calcd for C 30 H 19 O 10 , 539.097 3); 1H NMR (400 MHz, DMSO-d6) δ: 8.02 (2H, d, J = 8.4 Hz, H-2', H-6'), 7.97 (2H, d, J = 8.4 Hz, H-2'", H-6"'), 7.05 (2H, d, J = 8.4 Hz, H-3', H-5'), 6.94 (2H, d, J = 8.4 Hz, H-3'", H-5"'), 6.88 (2H, s, H-3, H-3"), 6.75 (1H, s, H-8"), 6.50 (1H, d, J = 2.0 Hz, H-8), 6.22 (1H, d, J = 2.0 Hz, H-6); 13 C NMR (100 MHz, DMSO-d6) δ: 164.3 (C-2), 103.9 (C-3), 181.7 (C-4), 160.5 (C-5), 99.0 (C-6), 163.0 (C-7), 94.6 (C-8), 157.0 (C-9), 104.0 (C-10), 124.2 (C-l'), 128.2 (C-2', C-6'), 115.4 (C-3', C-5'), 161.2 (C-4'), 164.2 (C-2"), 102.7 (C-3"), 182.0 (C-4"), 153.0 (C-5"), 124.8 (C-6"), 157.5 (C-7"), 94.0 (C-8"), 153.8 (C-9"), 104.3 (C-10"), 121.0 (C-l"'), 128.5 (C-2'", C-6"'), 116.0 (C-3'", C-5"'), 161.4 (C-4"'). The above data are in agreement with the reported data in the literature

[29] The reported data are basically consistent, so compound 10 is identified as hinokiflavone.

[0031] The results of the α-glucosidase inhibitory activity test: The results of the α-glucosidase inhibitory activity test show that compound 8 has obvious α-glucosidase inhibitory activity, with an IC 50 value of 42.68 ± 1.54 μM, and the activity intensity is basically comparable to that of the positive control acarbose (IC 50 = 40.25 ± 1.08 μM). Compounds 7, 9 and 10 show moderate α-glucosidase inhibitory activity, with IC 50 values of 72.14 ± 2.67, 61.26 ± 4.32 and 55.43 ± 2.17 μM, respectively. The rest of the compounds do not show obvious inhibitory activity on α-glucosidase.

[0032] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are within the scope of protection of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. The application of a composition of active components from *Selaginella tamariscina* in the preparation of a drug that inhibits α-glucosidase, characterized in that, The composition comprises 5,5′-dimethoxycaryophyllin A, cypress biflavonoids, isoflavone biflavonoids and cypress biflavonoids.

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