A mitochondrial-targeting paclitaxel derivative, its preparation method and application

Abstract

This invention belongs to the field of pharmaceutical technology, specifically relating to a mitochondrial-targeting paclitaxel derivative, its preparation method, and its application. The paclitaxel derivative of this invention has the structure shown in Formula I: [Formula omitted]; where n is an integer from 2 to 8. The derivative exhibits tumor mitochondrial targeting, and compared to the same dose of paclitaxel, this derivative increases the inhibition rate of tumor cell growth, effectively inhibiting colon cancer cells and breast cancer cells, while reducing toxicity to normal cells, thus significantly reducing adverse drug reactions. It can be used as a new, highly effective, low-toxicity, broad-spectrum antitumor drug.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical technology, specifically relating to a mitochondrial-targeting paclitaxel derivative, its preparation method, and its application. Background Technology

[0002] Paclitaxel is a natural product derived from diterpenoid alkaloids of the Taxus genus, possessing significant antitumor activity. Its mechanism of action primarily involves binding to tubulin, promoting microtubule polymerization while inhibiting microtubule depolymerization, thereby arresting tumor cell mitosis and achieving a proliferation-inhibiting effect. Based on its proven clinical efficacy, paclitaxel and related preparations have been widely used in the treatment of various malignant tumors, such as breast cancer, ovarian cancer, and non-small cell lung cancer, becoming a key component of monotherapy or combination therapy regimens.

[0003] However, paclitaxel still faces several technical challenges in clinical application that limit its efficacy. Firstly, due to its strong hydrophobicity and poor water solubility, existing injectable formulations typically require organic solvents for administration, which can easily trigger adverse reactions such as allergies and increase the complexity of clinical procedures. Secondly, the toxic side effects of systemic exposure limit the dosage and duration of treatment, narrowing its therapeutic window. Furthermore, tumor cells can develop acquired resistance or inherent tolerance through various mechanisms, leading to reduced treatment response or an increased risk of disease recurrence. Therefore, structural modification of paclitaxel to enhance its activity, or optimization of its administration strategy using novel drug delivery systems, has become an important direction of current research.

[0004] The cytotoxic effects of paclitaxel are closely related to mitochondrial homeostasis and the endogenous apoptosis pathway. In cases of paclitaxel resistance, tumor cells stabilize mitochondrial membrane potential and prevent cytochrome c release by upregulating the expression or function of anti-apoptotic proteins such as Bcl-2, thereby weakening apoptosis signaling and reducing sensitivity to drug-induced apoptosis. Therefore, enhancing the efficacy of paclitaxel in tumor cells and overcoming its mediated resistance while preserving its core pharmacodynamic framework remains a crucial issue that urgently needs to be addressed in this field of research. Summary of the Invention

[0005] To address the shortcomings of the existing technologies, the present invention aims to provide a mitochondrial-targeted paclitaxel derivative, its preparation method, and its applications. This invention targets the modifiable hydroxyl sites in the paclitaxel molecule by introducing alkyl chains of varying lengths as linking arms, covalently coupling mitochondrial-targeting cationic groups with the paclitaxel nucleus, thus designing and synthesizing a series of paclitaxel derivatives with mitochondrial-targeting capabilities. These derivatives aim to retain the microtubule-binding activity of paclitaxel while achieving specific accumulation of the drug within mitochondria through mitochondrial targeting, thereby enhancing mitochondrial localization and the endogenous apoptosis pathway, ultimately improving the killing efficacy of paclitaxel against tumor cells and laying a solid foundation for the clinical application of novel mitochondrial-targeted paclitaxel drugs.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A first aspect of the present invention provides a paclitaxel derivative, characterized in that it has the structure shown in Formula I: ; Where n is an integer between 2 and 8.

[0008] The paclitaxel derivative of this invention has tumor mitochondrial targeting. Compared with the same dose of paclitaxel, this derivative has an increased inhibition rate on tumor cell growth and reduced toxicity to normal cells, and can be used as a new, highly effective, low-toxicity, broad-spectrum antitumor drug.

[0009] In a more preferred embodiment of the present invention, n is preferably 2, 4, 6, or 8, and the derivative is selected from the following structures:

[0010] .

[0011] A second aspect of the present invention provides a method for preparing the above-mentioned paclitaxel derivative, comprising: using paclitaxel as a starting material, subjecting the C-2'-OH of paclitaxel to an esterification reaction to obtain an intermediate compound, and then subjecting the intermediate compound to a coupling reaction with F16 to generate the paclitaxel derivative shown in Formula I; The structure of the intermediate compound is shown in Formula III: ; F16 is 3-[2-(4-pyridyl)vinyl]-1H-indole, with the structure shown in Formula II: ; Where n is an integer between 2 and 8.

[0012] In some embodiments provided by this invention, the method is implemented via the following reaction pathway: ; Where n is an integer from 2 to 8; In some embodiments of the present invention, the esterification reaction is carried out using the EDCI / DMAP method. The condensing agent for the esterification reaction is selected from one or more of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI), dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-hydroxybenzotriazole, and 4-dimethylaminopyridine, preferably EDCI. The catalyst for the esterification reaction is selected from one or more of 4-dimethylaminopyridine (DMAP), triethylamine (TEA), and N,N-diisopropylethylamine (DIPEA), preferably DMAP. The solvent for the esterification reaction is selected from one or more of dichloromethane and dimethylformamide, preferably chlorine dioxide.

[0013] In some embodiments of the present invention, the esterification reaction temperature is 0 ℃-25 ℃, and the reaction time is 6-12 h.

[0014] In some embodiments of the present invention, the coupling reaction organic solvent is selected from one or a combination of two of acetonitrile and toluene; preferably acetonitrile.

[0015] In some embodiments of the present invention, the coupling reaction is carried out under reflux conditions at 75 ℃-95 ℃ for a reaction time of 24-36 h.

[0016] In some embodiments of the present invention, the method includes: using paclitaxel as a starting material, reacting it with... An esterification reaction was carried out, and the reaction was detected to be complete, yielding a clear white intermediate solution. The intermediate compound was then separated. Subsequently, an etherification reaction was carried out with F16 using acetonitrile as a solvent under reflux conditions at 75 ℃-95 ℃. After the reaction was detected to be complete, the compound shown in Formula I of this invention was separated.

[0017] In the method described above, paclitaxel, EDCI, DMAP, The ratio of added dichloromethane was 1 mmol: 1 mmol: 3 mmol: 2 mmol: 34 mL; the molar ratio of intermediate compound to F16 was 1:(1.2-1.8).

[0018] It should be understood that, based on the disclosure of this invention, those skilled in the art can further optimize the reaction conditions, such as selecting alternative solvents from more commonly used reagents in the art, or further increasing or decreasing the proportion of substances disclosed in this invention during conventional adjustments to obtain higher yields or reduce the generation of impurities. Of course, it should also be understood that, after each reaction step, those skilled in the art can choose to purify the product to make the next reaction more accurate, and conventional purification methods can be selected or chosen after conventional experiments.

[0019] A third aspect of the present invention provides a pharmaceutical composition comprising the above-described paclitaxel derivative.

[0020] In a fourth aspect, the present invention provides a pharmaceutical formulation comprising the above-described paclitaxel derivative and at least one pharmaceutically acceptable carrier or excipient.

[0021] The term "composition" as used in this invention refers to a pharmaceutical product comprising a therapeutically effective amount of a specified ingredient, as well as any product produced directly or indirectly from a combination of specified amounts of the specified ingredients.

[0022] The paclitaxel derivatives of the present invention, or pharmaceutical compositions or formulations containing them, can be administered in unit doses. The dosage form can be a liquid or a solid. Liquid dosage forms can be true solutions, colloids, microparticles, emulsions, or vortexes. Other dosage forms include tablets, capsules, pellets, aerosols, pills, powders, solutions, suspensions, emulsions, granules, suppositories, lyophilized powders for injection, inclusion complexes, etc.

[0023] The pharmaceutical compositions or formulations of the present invention may also contain commonly used carriers, including but not limited to: ion exchangers, alumina, aluminum stearate, lecithin, serum proteins such as human serum albumin, buffering substances (such as phosphates, glycerol, sorbitol, potassium sorbate, a mixture of partial glycerides of saturated vegetable fatty acids, water, salts) or electrolytes, protamine sulfate, disodium hydrogen phosphate, potassium hydrogen phosphate, sodium chloride, zinc salts, colloidal silica, magnesium trisilicate, polyvinylpyrrolidone, cellulose substances, polyethylene glycol, sodium carboxymethyl cellulose, polyacrylate, beeswax, lanolin, etc. The carrier content in the pharmaceutical composition or formulation can be 1 wt% to 98 wt%, typically approximately 80 wt%. For convenience, preservatives, buffers, etc., can be directly dissolved in the carrier.

[0024] Pharmaceutically acceptable excipients include, but are not limited to, excipients, which may be binders, fillers, lubricants, disintegrants, buffers, stabilizers, preservatives, etc. Excipients refer to components in a pharmaceutical composition or formulation other than the active ingredient, which are non-toxic to the subject and can coexist stably with the active pharmaceutical ingredient or can coexist stably with it using appropriate means.

[0025] Oral tablets and capsules may contain binders such as syrup, gum arabic, sorbitol, astragalus gum, or polyvinylpyrrolidone; fillers such as lactose, sucrose, corn starch, calcium phosphate, sorbitol, or glycine; lubricants such as magnesium stearate, talc, polyethylene glycol, or silica; disintegrants such as potato starch; or acceptable wetting agents such as sodium lauryl sulfate. Tablets may be coated using pharmaceutically known methods.

[0026] Oral liquids can be formulated as water and oil suspensions, solutions, emulsions, syrups, or as dry products, to be replenished with water or other suitable media before use. These liquid formulations may contain conventional additives such as suspending agents, sorbitol, cellulose methyl ether, glucose syrup, gelling agents, hydroxyethyl cellulose, carboxymethyl cellulose, aluminum stearate gel, hydrogenated edible oils, emulsifiers such as lecithin, sorbitan monooleate, and gum arabic; or non-aqueous carriers (which may contain edible oils such as almond oil), oils such as glycerin, ethylene glycol, or ethanol; preservatives such as methylparaben or propylparaben, and sorbic acid. Flavorings or colorings may be added if desired.

[0027] For parenteral administration, liquid dosage forms are typically made from a compound and a sterilized carrier. Water is the preferred carrier. Depending on the chosen carrier and drug concentration, the compound can be either dissolved in the carrier or prepared as a suspension. When preparing an injectable solution, the compound is first dissolved in water, filtered, sterilized, and then packaged into sealed bottles or ampoules.

[0028] In a fifth aspect of the invention, a drug carrier targeting mitochondria is provided, comprising the above-described paclitaxel derivative.

[0029] In embodiments of the present invention, it has been verified that the paclitaxel derivative of the present invention can selectively accumulate in the mitochondria of tumor cells by utilizing the difference in membrane potential of tumor cells, thus exhibiting excellent mitochondrial targeting in tumor cells.

[0030] In a sixth aspect of the invention, a drug delivery system is provided, comprising the above-described paclitaxel derivative or the above-described mitochondrial-targeting drug carrier. The paclitaxel derivative of the present invention, due to its excellent targeting of tumor cell mitochondria, can serve as a drug delivery system or a major component of such a system, selectively delivering more active drugs into the mitochondria of tumor cells, thereby achieving a good tumor therapeutic effect.

[0031] In a seventh aspect of the invention, the use of the above-described paclitaxel derivative or pharmaceutical composition or drug carrier or drug delivery system in the preparation of an antitumor drug is provided.

[0032] The tumors mentioned are skin cancer, head and neck cancer, lung cancer, esophageal cancer, cervical cancer, uterine cancer, pancreatic cancer, breast cancer, kidney cancer, ureteral cancer, bladder cancer, colon cancer, pharyngeal squamous cell carcinoma, basal cell carcinoma or melanoma, tongue cancer, pharyngeal squamous cell carcinoma, malignant lymphoma, laryngeal squamous cell carcinoma, lung squamous cell carcinoma, small cell carcinoma, esophageal squamous cell carcinoma, cervical cancer or glioma.

[0033] In embodiments of the present invention, the compounds of the present invention exhibit good antitumor activity against breast cancer or colon cancer, significantly superior to paclitaxel.

[0034] Furthermore, the present invention also provides a method for treating tumors, comprising administering to a subject a therapeutically effective dose of the paclitaxel derivative described in the first aspect above, or the pharmaceutical composition described in the third aspect above, or the pharmaceutical preparation described in the fourth aspect above, or the mitochondrial-targeting drug carrier described in the fifth aspect above, or the drug delivery system described in the sixth aspect above, wherein the tumor particularly refers to colon or breast cancer; the subject refers to an animal, preferably a mammal, and most preferably a human, that is already the subject of treatment, observation, or experimentation. The term "therapeutically effective dose" refers to the amount of the active compound or pharmaceutical preparation, including the compound of the present invention, that can elicit a biological or medical response in an tissue system, animal, or human sought by the researcher, veterinarian, physician, or other medical professional, including the reduction or partial reduction of symptoms of the treated disease, syndrome, symptom, or disorder. It must be recognized that the optimal dosage and interval of the active ingredient described in the present invention are determined by its properties and external conditions such as the form, route, and site of administration, and the specific mammal being treated, and this optimal dosage can be determined using conventional techniques. It must also be recognized that the optimal duration of treatment, i.e., the daily dose of the compound over a specified period of time, can be determined using methods known in the art.

[0035] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: This invention belongs to the field of pharmaceutical technology, specifically relating to a new class of paclitaxel derivatives. These derivatives have tumor mitochondrial targeting properties. Compared with the same dose of paclitaxel, these derivatives have an increased inhibition rate on tumor cell growth, effectively inhibiting colon cancer cells and breast cancer cells, while reducing toxicity to normal cells. This significantly reduces adverse drug reactions and can be used as a new, highly effective, low-toxicity, broad-spectrum antitumor drug. Attached Figure Description

[0036] Figure 1 This is a schematic diagram illustrating the preparation of the paclitaxel-F16 conjugate modified at the C2′ position in an embodiment of the present invention; Figure 2 This is the ¹H NMR spectrum (600 M, CD3OD) of compound 1 in the embodiment of the present invention. Figure 3 This is the ¹H NMR spectrum (600 M, CD3OD) of compound 2 in the embodiment of the present invention. Figure 4 The ¹H NMR spectrum (600 M, CD3OD) of compound 3 in this embodiment of the invention is shown. Figure 5 This is the ¹H NMR spectrum (600 M, CD3OD) of compound 4 in the embodiment of the present invention. Figure 6 These are confocal microscopy images of mitochondria in MDA-MB-435 cells treated with compound 3 in this embodiment of the invention; wherein, (a) is the fluorescence of the mitochondrial dye Mito-Tracker Red (593-643 nm); (b) is the fluorescence of compound 3 (427-520 nm); and (c) is an overlay of a and b. Detailed Implementation

[0037] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0038] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, and / or combinations thereof.

[0039] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0040] Example 1 Preparation of compound 1: .

[0041] Paclitaxel (50.0 mg, 58.6 μmol) was added to a solution of 4-bromobutyric acid (9.80 mg, 58.6 μmol), EDCI (33.4 mg, 176 μmol), and DMAP (14.3 mg, 117 μmol) in dichloromethane (2 mL), and the mixture was stirred at room temperature for 8 h. The mixture was then diluted with dichloromethane, extracted three times with saturated brine, and the organic phases were combined, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and purified by silica gel column chromatography (DCM:MeOH = 40:1) to obtain a white intermediate (53.4 mg). The intermediate was added to a solution of anhydrous acetonitrile (5 mL) containing F16 (14.1 mg, 63.8 μmol), and refluxed at 85 °C for 24 h. The reaction system was concentrated under reduced pressure and purified by silica gel column chromatography (DCM:MeOH = 15:1) to obtain 39.8 mg of yellow solid, namely compound 1 (yield 55.6%). 1 The H NMR spectrum is attached. Figure 3 NMR data: 1 H NMR (600 MHz, CD3OD) δ 8.47 (d, J = 7.2 Hz, 2H), 8.16 (d, J = 15.6 Hz, 1H), 8.11 (dd, J = 1.2, 8.4 Hz,2H), 8.09 – 8.06 (m, 1H), 7.90 (d, J = 7.2 Hz, 2H), 7.86 (s, 1H), 7.83 (dd, J =1.2, 8.4 Hz, 2H), 7.70 – 7.66 (m, 1H), 7.61 – 7.57 (m, 2H), 7.55– 7.51 (m,3H), 7.50 – 7.44 (m, 5H), 7.32 – 7.26 (m, 3H), 7.23 – 7.19 (d, J = 16.2 Hz,1H), 6.46 (s, 1H), 6.08 (td, J = 1.8, 9.0 Hz, 1H), 5.87 (d, J = 6.0 Hz, 1H), 5.64(d, J = 7.2 Hz, 1H), 5.49 (d, J = 6.6 Hz, 1H), 4.94 (dd, J= 2.4, 9.6 Hz, 1H), 4.50– 4.41 (m, 2H), 4.32 (dd, J = 6.6, 10.8 Hz, 1H), 4.17 (s, 2H), 3.80 (d, J = 7.2Hz, 1H), 2.67 – 2.60 (m, 2H), 2.48 – 2.43 (m, 1H), 2.37 (s, 3H), 2.34 – 2.28(m, 2H), 2.20 – 2.14 (m, 4H), 1.96 (d, J = 1.2 Hz, 3H), 1.86 – 1.77 (m, 2H), 1.65 (s, 3H), 1.14 (s, 3H), 1.12 (s, 3H). Example 2 Preparation of compound 2: .

[0042] Paclitaxel (50.0 mg, 58.6 μmol) was added to a solution of 6-bromohexanoic acid (11.4 mg, 58.6 μmol), diisopropylcarbodiimide (DIC) (30.7 mg, 176 μmol), and DMAP (14.3 mg, 117 μmol) in dichloromethane (2 mL), and the mixture was stirred at room temperature for 8 h. The mixture was then diluted with dichloromethane, extracted three times with saturated brine, and the organic phases were combined, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and purified by silica gel column chromatography (DCM:MeOH = 40:1) to obtain a white intermediate (56.7 mg). The intermediate was added to a solution of anhydrous acetonitrile (5 mL) containing F16 (21.9 mg, 99.4 μmol), and refluxed at 85 °C for 24 h. The reaction system was concentrated under reduced pressure and purified by silica gel column chromatography (DCM:MeOH = 18:1) to obtain 43.4 mg of yellow solid, namely compound 2 (yield 59.2%). 1 The H NMR spectrum is attached. Figure 4 NMR data: 1 HNMR (600 MHz, CD3OD) δ 8.52 (d, J = 7.2 Hz 2H), 8.20 (d, J = 15.6 Hz 1H), 8.11 –8.07 (m,3H), 8.01(d, J=7.2 Hz, 2H), 7.86 – 7.81 (m, 3H), 7.70 – 7.67 (m, 1H), 7.61 – 7.57 (m,2H), 7.56 – 7.53 (m, 1H), 7.49 – 7.45 (m, 5H), 7.44 – 7.41 (m,2H), 7.29 – 7.23 (m, 4H), 6.44 (s, 1H), 6.00 (td, J = 1.8, 9.0 Hz, 1H), 5.77 (d, J = 7.2 Hz, 2H), 5.62 (d, J = 7.2 Hz, 1H), 5.44 (d, J = 7.2 Hz, 1H), 4.96 (dd, J =2.4, 9.6 Hz, 1H), 4.38 (td, J = 2.4, 7.2 Hz, 2H), 4.31 (dd, J = 6.6, 10.8 Hz, 2H), 4.17 (s, 2H), 3.78 (d, J = 7.2 Hz, 1H), 2.57 – 2.42 (m, 3H), 2.36 (s, 3H), 2.16(s, 3H), 2.10 (dd, J = 9.0, 15.6 Hz,1H), 1.98 – 1.90 (m, 5H), 1.82 – 1.77 (m,1H), 1.76 – 1.68 (m, 3H), 1.64 (s, 3H), 1.45 – 1.38 (m, 2H), 1.14 (s, 3H),1.12 (s, 3H). Example 3 Preparation of compound 3: .

[0043] Paclitaxel (50.0 mg, 58.6 μmol) was added to a solution of dimethylformamide (2 mL) containing 8-bromooctanoic acid (13.1 mg, 58.6 μmol), EDCI (33.4 mg, 176 μmol), and DMAP (14.3 mg, 117 μmol) under ice bath conditions, and the mixture was stirred at room temperature for 8 h. The mixture was then diluted with dichloromethane, extracted three times with saturated brine, and the organic phases were combined, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and purified by silica gel column chromatography (DCM:MeOH = 40:1) to give a white intermediate (55.2 mg). The intermediate was added to a solution of toluene (5 mL) containing F16 (17.2 mg, 78.2 μmol), and heated at 75 °C for 24 h. The reaction system was concentrated under reduced pressure and purified by silica gel column chromatography (DCM:MeOH = 20:1) to obtain 44.2 mg of yellow solid, namely compound 3 (yield 66.3%). 1 The H NMR spectrum is attached. Figure 5 NMR data: 1 H NMR (600MHz, CD3OD) δ 8.53 (d, J = 6.6 Hz, 2H), 8.19 (d, J = 15.6 Hz, 1H), 8.12 – 8.06(m, 3H), 8.00 (d, J = 7.2 Hz, 2H), 7.86 – 7.80 (m, 3H), 7.71 – 7.66 (m, 1H), 7.62 – 7.57 (m, 2H), 7.56 – 7.52 (m, 1H), 7.50 – 7.42 (m, 7H), 7.29 – 7.23(m, 4H), 6.45 (s, 1H), 6.02 (td, J = 1.2, 9.0 Hz, 1H), 5.80 (d, J = 6.6 Hz, 1H), 5.63 (d, J = 7.8 Hz, 1H), 5.47 (d, J = 7.2 Hz, 1H), 4.98 (dd, J = 2.4, 9.6 Hz, 1H), 4.38 (td, J = 1.8, 7.2 Hz, 2H), 4.32 (dd, J = 6.6, 11.4 Hz, 1H), 4.18 (s, 2H), 3.80 (d,J = 7.2 Hz, 1H), 2.50 – 2.43 (m, 3H), 2.38 (s, 3H), 2.16 – 2.10 (m,4H), 1.96 – 1.89 (m, 5H), 1.82 – 1.73 (m, 2H), 1.68 – 1.62 (m, 5H), 1.38 –1.32 (m, 6H), 1.14 (s, 3H), 1.11 (s, 3H). Example 4 Preparation of compound 4: .

[0044] Paclitaxel (50.0 mg, 58.6 μmol) was added to a solution of 10-bromodecanoic acid (14.2 mg, 58.6 μmol), DCC (36.3 mg, 176 μmol), and HOBt (17 mg, 117 μmol) in dichloromethane (2 mL), and the mixture was stirred at room temperature for 8 h. The mixture was then diluted with dichloromethane, extracted three times with saturated brine, and the organic phases were combined, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and purified by silica gel column chromatography (DCM:MeOH = 50:1) to give a white intermediate (57.9 mg). The intermediate was added to a solution of toluene (5 mL) containing F16 (19.0 mg, 86.2 μmol), and heated at 95 °C for 24 h. The reaction mixture was concentrated under reduced pressure and purified by silica gel column chromatography (DCM:MeOH = 25:1) to give 48.1 mg of a yellow solid, compound 4 (yield 62.8%). 1 The H NMR spectrum is attached. Figure 5 NMR data: 1 H NMR (600 MHz, CD3OD) δ 8.53 (d, J = 7.2 Hz, 2H), 8.18 (d, J = 15.6 Hz, 1H), 8.11 (dd, J = 1.2, 8.4 Hz,2H), 8.09 – 8.06 (m, 1H), 8.00 (d, J= 7.2 Hz, 2H), 7.84 (s, 1H), 7.83 – 7.80(m, 2H), 7.70 – 7.66 (m, 1H), 7.61 – 7.57 (m, 2H), 7.55 – 7.52 (m, 1H), 7.50– 7.42 (m, 7H), 7.29 – 7.22 (m, 4H), 6.45 (s, 1H), 6.02 (td, J = 1.8, 9.0 Hz, 1H), 5.80 (d, J = 7.2 Hz, 1H), 5.63 (d, J = 7.8 Hz, 1H), 5.48 (d, J = 6.6 Hz, 1H), 4.99 (dd, J = 2.4, 9.6 Hz, 1H), 4.39 (t, J = 7.2 Hz, 2H), 4.33 (dd, J = 6.6, 11.4Hz, 1H), 4.18 (s, 2H), 3.80 (d, J = 7.2 Hz, 1H), 2.49 – 2.43 (m, 3H), 2.39 (s,3H), 2.17 – 2.11 (m, 4H), 1.98 – 1.90 (m, 5H), 1.83 – 1.73 (m, 2H), 1.67 –1.59 (m, 5H), 1.37 – 1.26 (m, 10H), 1.14 (s, 3H), 1.11 (s, 3H). Example 5 In vitro antitumor experiment MTT assay for tumor cell viability: Logarithmic growth phase cells were digested with trypsin and prepared into a single-cell suspension of a specific concentration. 5000 cells / well were seeded into 96-well plates, with 100 μL of cell suspension added to each well. The next day, the old culture medium was removed, and fresh culture medium containing different concentrations of the drug and corresponding solvent controls was added, 200 μL to each well. Five dose groups (0.032, 0.16, 0.80, 4.0, 20 μM) were set up for each test compound (1-4), with three parallel wells per group. The cells were cultured at 37℃ and 5% CO2 for 48 h. After culturing, the supernatant was discarded, and 200 μL of freshly prepared serum-free culture medium containing 0.5 mg / mL MTT was added to each well. Continue culturing for 4 h, discard the supernatant, add 150 μL LDMSO to each well to dissolve the formazan precipitate, shake well in a microplate reader, and measure the optical density (OD) at a detection wavelength of 570 nm. Use the solvent-treated tumor cells as the control group. Calculate the cell viability of the tumor cells according to the following formula, and calculate the IC50 according to the intermediate-efficiency equation:

[0045] The results are shown in Table 1.

[0046] Table 1: In vitro antitumor detection of compounds 1-4

[0047] Taxol: Paclitaxel; Hct116: Human colon cancer cell line; MDA-MB-231: Triple-negative breast cancer cell line; MDA-MB-435: Triple-negative breast cancer cell line; Qsg-7701: Human normal stem cell line.

[0048] Example 6 Intracellular fluorescence imaging Logarithmic growth phase MDA-MB-435 cells were digested with trypsin and prepared into a single-cell suspension of a certain concentration. Tumor cells were seeded at 20,000 cells per well in a glass-bottomed culture dish system, with 2 mL of cell suspension added. The next day, the old culture medium was removed, and 2 mL of fresh culture medium containing the drug (200 nM) was added for incubation for 24 h. Subsequently, the culture medium was removed, and 1 mL of Mito-Tracker Red (5 μM) working solution was added. The cells were incubated at 37 ℃ in the dark for 15-30 min. After washing 2-3 times with PBS, fresh culture medium was added for live-cell laser confocal imaging. Imaging was performed using a laser confocal microscope (Leica), acquiring fluorescence signals in the wavelength ranges of 427-520 nm and 593-643 nm, respectively. The fluorescence images and their overlays were analyzed using Las-X software. The results are shown in [Figure number missing]. Figure 6(a) Fluorescence of mitochondrial dye Mito-Tracker Red (593–643 nm); (b) Fluorescence of compound 3 (427–520 nm); (c) Overlay of a and b. The colocalization analysis results of compound 3 and Mito-Tracker Red are as follows: Pearson's Correlation: 0.4678, Overlap Coefficient: 0.6460, Colocalization Rate: 63.83%.

[0049] The co-localization experiment of compound 3 and Mito-Tracker Red in mitochondria can verify that the F16-modified paclitaxel derivative can be targeted and delivered to the mitochondria of tumor cells.

[0050] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of them. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A paclitaxel derivative, characterized in that, It has the structure shown in Equation I: ； Where n is an integer between 2 and 8.

2. The paclitaxel derivative according to claim 1, characterized in that, The derivative is selected from the following structures: 。 3. A method for preparing the paclitaxel derivative as described in claim 1 or 2, characterized in that, include: Starting with paclitaxel, the C-2′-OH of paclitaxel is esterified to obtain an intermediate compound. Then, the intermediate compound is coupled with F16 to generate the paclitaxel derivative shown in Formula I. The intermediate structure is shown in Equation III: Where n is an integer from 2 to 8; F16 is 3-[2-(4-pyridyl)vinyl]-1H-indole, with the structural formula shown in Formula II: .

4. The method according to claim 3, characterized in that, The method is achieved through the following reaction pathway: ； Where n is an integer from 2 to 8; Preferably, the condensing agent for the esterification reaction is selected from one or a combination of several of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-hydroxybenzotriazole, and 4-dimethylaminopyridine; the solvent for the esterification reaction is selected from one or a combination of two of dichloromethane and dimethylformamide. Preferably, the esterification reaction temperature is 0 ℃-25 ℃, and the reaction time is 6-12 h; Preferably, the organic solvent for the coupling reaction is selected from one or a combination of two of acetonitrile and toluene; Preferably, the coupling reaction is carried out under reflux conditions at 75 ℃-95 ℃ for 24-36 h. Preferably, the molar ratio of the intermediate compound to F16 is 1:(1.2-1.8).

5. A pharmaceutical composition, characterized in that, It includes the paclitaxel derivative as described in claim 1 or 2.

6. A pharmaceutical preparation, characterized in that, It comprises the paclitaxel derivative of claim 1 or 2 and at least one pharmaceutically acceptable carrier or excipient.

7. A drug carrier targeting mitochondria, characterized in that, It includes the paclitaxel derivative as described in claim 1 or 2.

8. A drug delivery system, characterized in that, It comprises the paclitaxel derivative of claim 1 or 2 or the drug carrier of claim 7.

9. The use of the paclitaxel derivative of claim 1 or 2, the pharmaceutical composition of claim 5, the drug carrier of claim 7, or the drug delivery system of claim 8 in the preparation of antitumor drugs.

10. The application according to claim 9, characterized in that, The tumors mentioned are skin cancer, head and neck cancer, lung cancer, esophageal cancer, cervical cancer, uterine cancer, pancreatic cancer, breast cancer, kidney cancer, ureteral cancer, bladder cancer, colon cancer, pharyngeal squamous cell carcinoma, basal cell carcinoma or melanoma, tongue cancer, pharyngeal squamous cell carcinoma, malignant lymphoma, laryngeal squamous cell carcinoma, lung squamous cell carcinoma, small cell carcinoma, esophageal squamous cell carcinoma, cervical cancer or glioma; preferably breast cancer or colon cancer.

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