Discovery of ellagic acid as a competitive inhibitor of Src homology phosphotyrosyl phosphatase 2 (SHP2) for cancer treatment: In vitro and in silico study.

Targeting SHP2 has become a potential cancer treatment strategy. In this study, ellagic acid was first reported as a competitive inhibitor of SHP2, with an IC50 value of 0.69 ± 0.07 µM, and its inhibitory potency was 34.86 times higher that of the positive control NSC87877. Ellagic acid also had high inhibitory activity on the SHP2-E76K and SHP2-E76A mutants, with the IC50 values of 1.55 ± 0.17 µM and 0.39 ± 0.05 µM, respectively. Besides, the IC50 values of ellagic acid on homologous proteins SHP1, PTP1B, and TCPTP were 0.93 ± 0.08 µM, 2.04 ± 0.28 µM, and 11.79 ± 0.83 µM, with selectivity of 1.35, 2.96, and 17.09 times, respectively. The CCK8 proliferation experiment exhibited that ellagic acid would inhibit the proliferation of various cancer cells. It was worth noting that the combination of ellagic acid and KRASG12C inhibitor AMG510 would produce a strong synergistic effect in inhibiting NCI-H358 cells. Western blot experiment exhibited that ellagic acid would downregulate the phosphorylation levels of Erk and Akt in NCI-H358 and MDA-MB-468 cells. Molecular docking and molecular dynamics studies revealed the binding information between SHP2 and ellagic acid. In summary, this study provides new ideas for the development of SHP2 inhibitors.

Evaluation of retinal microvasculature in exotropia with abnormal binocular vision by optical coherence tomography angiography.

BACKGROUND: To explore the retinal microvasculature in large-angle concomitant exotropia patients with abnormal binocular vision using optical coherence tomography angiography (OCTA) analysis. METHODS: OCTA images of 52 healthy and 100 strabismic eyes were analyzed to quantify the retinal thickness (RT), superficial capillary plexus (SCP), deep capillary plexus (DCP), and foveal avascular zone (FAZ). Paired t-tests were performed to compare differences between the two groups, the dominant eye and the deviated eye in the exotropia group, respectively. A p-value < 0.01 was considered significant. RESULTS: The mean angle of deviation was 79.38 [± 25.64] (prism diopters, PD). There were significant differences in the DCP in deviated eyes between the exotropia group and the control group (fovea: p = 0.007; temporal: p = 0.014; nasal: p = 0.028; inferior: p = 0.013). The temporal SCP in the exotropia group was significantly higher than in the control group in deviated eyes (p = 0.020). No significant difference was found between dominant eyes and strabismic eyes (p > 0.01). CONCLUSIONS: The study showed that OCTA revealed subnormal DCP in patients with large-angle exotropia and abnormal binocularity which may be related to retinal suppression. Changes in the macular microvasculature may provide valuable insights into the development of strabismus. Further studies are needed to determine the clinical relevance of this finding. TRIAL REGISTRATION: This trial is registered as ChiCTR2100052577 at www.Chictr.org.cn .

Establishment and verification of a digital PCR assay for the detection of CK19 expression in quantitative analysis of circulating tumor cell.

The objective of this study was to establish and verify a digital PCR assay for the detection of CK19 gene expression, and to use it to detect circulating tumor cells (CTC) by taking advantages of its ultra-high sensitivity and absolute quantitation. Firstly, the primers and probes were designed according to the mRNA sequence of CK19 gene, and housekeeping gene ABL1 was used as the internal control. The best candidate was screened by human breast cancer MCF7 cells and healthy human leukocytes from 13 sets of primer and probes and verified by direct sequencing. Secondly, after the reaction conditions of the selected primers and probes were optimized, limit of blank (LOB) analysis were performed with different concentrations of cDNAs as templates from healthy human leukocytes. The results revealed the LOB of CK19 with ABL1 copy numbers of 20,000, 15,000, 10,000, 5000 and 2500 were 9.24, 8.93, 3.12, 3.17 and 2.53 copies, respectively. Thirdly, the different concentrations of cDNAs from MCF7 cells and healthy human leukocytes were premixed and used in the limit of detection (LOD) analysis, which showed that the CK19 gene could be effectively detected at the concentration ratio of 50%, 10%, 5%, 1%, 0.5% and 0.1%, and the linear R2 value was 0.9998. Finally, the preliminary results of digital PCR in clinical samples indicated that CK19 copy numbers were higher in advanced breast cancer patients than healthy controls. The above results demonstrated the advantages of our CK19 digital PCR assay in sensitivity, specificity, and accurate quantification. If verified further, the assay is expected to play significant roles in the quantitative analysis of CTC in breast cancer with a good application prospect.

Effects of seasonal grazing on plant and soil microbial diversity of typical temperate grassland.

Biodiversity is the decisive factor of grassland ecological function and process. As the most important human use of grassland, grazing inevitably affects the grassland biodiversity. However, comprehensive studies of seasonal grazing on plant and soil bacterial, archaeal and fungal diversity of typical temperate grassland are still lacking. We examined the impact of seasonal grazing, including no-grazing (NG), continuous grazing (CG), grazing in May and July (G57), grazing in June and August (G68), and grazing in July and September (G79) on grassland plant and soil microbial diversity based on a long-term field grazing experiment. The results showed that the aboveground plant biomass (AGB) of the seasonal grazing plots was significantly higher than that of the CG plots. Compared with NG, CG increased significantly the Margalef richness index of plant community, while did not significantly change the Shannon, Simpson and Pielou evenness of plant community. Grazing changed the composition and biomass of dominant vegetation. Long-term grazing decreased the proportion of Leymus chinensis (Trin.) Tzvel. and increased the proportion of Cleistogenes squarrosa (Trin.) Keng. There was no significant change in the Shannoneven, Shannon and Coverage indices of soil bacteria, archaea and fungi between NG and the grazing plots. But the Chao index of soil fungi in G57, G68 and G79 and archaea in G57, G79 was significantly higher than that in CG. The results of correlation analysis showed that the plant diversity in the CG plots was significantly negatively correlated with the soil bacterial diversity. The plant richness in the G57 and G68 plots was significantly positively correlated with the soil archaea richness. Our study showed that seasonal grazing was a sustainable grazing management strategy for maintaining typical grassland plant and soil microbial diversity in northern of China.

Differential transcriptomic landscapes of multiple organs from SARS-CoV-2 early infected rhesus macaques.

SARS-CoV-2 infection causes complicated clinical manifestations with variable multi-organ injuries, however, the underlying mechanism, in particular immune responses in different organs, remains elusive. In this study, comprehensive transcriptomic alterations of 14 tissues from rhesus macaque infected with SARS-CoV-2 were analyzed. Compared to normal controls, SARS-CoV-2 infection resulted in dysregulation of genes involving diverse functions in various examined tissues/organs, with drastic transcriptomic changes in cerebral cortex and right ventricle. Intriguingly, cerebral cortex exhibited a hyperinflammatory state evidenced by significant upregulation of inflammation response-related genes. Meanwhile, expressions of coagulation, angiogenesis and fibrosis factors were also up-regulated in cerebral cortex. Based on our findings, neuropilin 1 (NRP1), a receptor of SARS-CoV-2, was significantly elevated in cerebral cortex post infection, accompanied by active immune response releasing inflammatory factors and signal transmission among tissues, which enhanced infection of the central nervous system (CNS) in a positive feedback way, leading to viral encephalitis. Overall, our study depicts a multi-tissue/organ transcriptomic landscapes of rhesus macaque with early infection of SARS-CoV-2, and provides important insights into the mechanistic basis for COVID-19-associated clinical complications.

Transcatheter arterial chemoembolization improves clinical efficacy and life quality of patients with lung cancer and reduces adverse reactions.

OBJECTIVE: To determine the clinical efficacy and safety of transcatheter arterial chemoembolization (TACE) for patients with lung cancer (LC). METHODS: A total of 513 inpatients with LC admitted to our hospital from January 2012 to January 2020 were analyzed retrospectively. Based on different treatment methods, they were assigned into a control group (CG; n=249) for traditional bronchial artery infusion (BAI) and an experimental group (EG; n=264) for TACE, with shared chemotherapy drugs and treatment courses. The two groups were compared with respect to clinical efficacy, pre- and post-treatment pulmonary function, adverse reactions, as well as negative emotions and quality of life (QoL) scores. RESULTS: The curative effect in EG was far superior to CG (P<0.05). In comparison with CG, the pulmonary function in EG was better and the incidence of adverse reactions was lower after treatment (P<0.05). The negative emotions and the QoL were improved in both groups, with more distinct improvement in EG compared with CG (P<0.05). CONCLUSIONS: With higher safety and efficacy, TACE can improve the clinical efficacy and QoL of patients with LC while relieving bad mood and reducing adverse reactions.

Heteropoly Blue/Protonation-Defective Graphitic Carbon Nitride Heterojunction for the Photo-Driven Nitrogen Reduction Reaction.

The establishment of a heterojunction is a crucial strategy to design highly effective nonnoble metal nanocatalysts for the photocatalytic nitrogen reduction reaction (PNRR). Heteropoly blues (r-POMs) can act as electron-transfer mediators in PNRR, but its agglomeration limits the further promotion of PNRR productivity. In this work, we construct a protonation-modified surface of N-vacancy g-C3N4 (HV-C3N4), achieving the high dispersion of r-POMs via the surface modification strategy. Enlightened by the synergy effect of the nitrogenase, r-POMs were anchored onto HV-C3N4 nanosheets through an electrostatic self-assembly method for preparing r-POMs-based protonation-defective graphitic carbonitride (HV-C3N4/r-POMs). As an electron donor, r-PW12 can match with the energy level of HV-C3N4 to build a heterojunction. The electron redistribution of the heterojunction facilitates the optimization of the electronic structure for enhancing the performance of PNRR. HV-C3N4/r-PW12 exhibits the best PNRR efficiency of 171.4 µmol L-1 h-1, which is boosted by 94.39% (HV-C3N4) and 86.98% (r-PW12). The isotope 15NH4+ experiment proves that ammonia is derived from N2, not carbon nitride. This study opens up a crucial view to achieve the high dispersion of r-POMs nanoparticles and develop high-efficiency nonnoble metal photocatalysts for the PNRR.

Huang Qi Tong Bi Decoction Attenuates Myocardial Ischemia-Reperfusion Injury via HMGB1/TLR/NF-κB Pathway.

The aim of this study was to study the protective effect of Huang Qi Tong Bi Decoction (HQTBT) on the heart of rats. Ischemia-reperfusion injury was established by coronary artery ligation. Proinflammatory cytokines were decreased by XFZY in coronary artery ligated rats. ST segment was also restored with the treatment of HQTBT. Triphenyltetrazole chloride (TTC) staining and pathological analysis showed that HQTBT reduced myocardial injury. Besides, the expressions of HMGB1/TLR/NF-κB pathway in rats were significantly decreased by HQTBT. This study shows that HQTBT inhibited inflammatory reaction on myocardial injury in rats.

Alternate Ultrasound/Microwave Digestion for Deep Eutectic Hydro-distillation Extraction of Essential Oil and Polysaccharide from Schisandra chinensis (Turcz.) Baill.

An alternating synergetic ultrasound/microwave method was applied to the simultaneous extraction of essential oils and polysaccharides with deep eutectic solvent (DES) from Schisandra chinensis. Under the optimal conditions, extract in the selected choline chloride-ethylene glycol 1:3 solvent yielded 12.2 mL/kg and 8.56 g/100g of essential oils and polysaccharides, respectively. The free radical scavenging and immunological activities of the polysaccharides and the antioxidant activity of the essential oils have also been investigated. The lymphocyte proliferation capacity was substantially improved by adding concanavalin A or lipopolysaccharides to polysaccharides (0.20 mg/mL). The IC50 values of the essential oils for scavenging DPPH obtained by hydro-distillation and DES ultrasound/microwave-assisted hydro-distillation (DES UMHD) were 52.34 µg/mL and 29.82 µg/mL, respectively. The essential oil obtained by DES UMHD had the highest reducing power (856.05 (TE)/g) at 150 g/mL and had the strongest inhibitory capacity (SC% = 18.12%). S. chinensis has the potential to be developed as a natural antioxidant.

Ameliorative Effect of Dangguibuxue Decoction against Cyclophosphamide-Induced Heart Injury in Mice.

Dangguibuxue decoction (DBD), a kind of Chinese herbal medicine, has been widely used to treat blood deficiency disease in China. In this experiment, we studied the effects of the Dangguibuxue decoction (DBD) on the myocardial injury induced by cyclophosphamide in mice. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatine kinase (CK), and lactic dehydrogenase (LDH) in serum were detected by commercial kits. Total white blood cell (WBCs), platelets, and cytokines pathological changes of heart tissue were also examined. In addition, the protein levels of the NF-кB pathway were detected to reveal its mechanism. The results showed that DBD significantly decreased the levels of ALT, AST, CK, and LDH and increased WBCs in CTX-induced mice. In addition, DBD significantly alleviated pathological changes of heart tissue. DBD significantly reduced the protein expressions of NF-кB signaling pathway. In summary, DBD can be considered an effective drug to alleviate CTX-induced heart damage in mice.

GC-MS Study of the Chemical Components of Different Aquilaria sinensis (Lour.) Gilgorgans and Agarwood from Different Asian Countries.

As a traditional medicinal herb and valuable natural spice in China, Aquilaria sinensis (Lour.) Gilg has many significant pharmacological effects. Agarwood is the resinous heartwood acquired from wounded A. sinensis trees, and is widely used in pharmaceuticals owing to its excellent medicinal value. In this study, the chemical composition of volatile components and alcohol extracts from different organs of A. sinensis and agarwoods grown in different regions were investigated using GC-MS. The results showed that Vietnam agarwood had the highest moisture content, which was attributed to the local climate, while the fruit and bark of A. sinensis had higher moisture contents than the other organs. The volatile components of A. sinensis organs included 3-ethyl-5-(2-ethylbutyl)-octadecane, oleic acid 3-(octadecyloxy) propyl ester, and docosanoic acid 1,2,3-propanetriyl ester, while the alcohol extracts of A. sinensis organs contained benzoic acid ethyl ester, hexadecanoic acid ethyl ester, oleic acid, and n-hexadecanoic acid. Furthermore, the main active ingredients in agarwood from different habitats were sesquiterpenoids, aromatic species, and chromone compounds. The role of chromone compound 2-phenylethyl-benzopyran as an elicitor and the mechanism of agarwood formation were also investigated. Antioxidant tests showed that essential oils from agarwood and A. sinensis had antioxidant capacities by comparison with butylated hydroxytoluene and vitamin E. An antibacterial activity test showed that the inhibition effect of the essential oil was better against Gram-positive bacteria than against Gram-negative bacteria.

Effects of enhanced UV-B radiation on the nutritional and active ingredient contents during the floral development of medicinal chrysanthemum.

The paper mainly studied the effects of enhanced UV-B radiation on the nutritional and active ingredient contents during the floral development of medicinal chrysanthemum. The experiment included two levels of UV-B radiation (0 and 400µWcm(-2)). The contents of hydrogen peroxide (H2O2), anthocyanin, UV-B absorbing compounds, total chlorophyll and carotenoids, and the activities of phenylalanine ammonia lyase enzyme (PAL) and cinnamic acid-4-hydroxylase enzyme (C4H) in flowers significantly decreased with the floral development. However, the contents of soluble sugar, amino acid and total vitamin C in flowers significantly increased with the floral development. The contents of flavonoid and chlorogenic acid were significantly different in the four stages of floral development, and their highest contents were found in the bud stage (stage 2). In the four stages of floral development, enhanced UV-B radiation significantly increased the contents of H2O2, UV-B absorbing compounds, chlorophyll, carotenoids, soluble sugar, amino acid, vitamin C, flavonoid and chlorogenic acid, and the activities of PLA and C4H in flowers. The results indicated that the highest contents of active and nutrient ingredients in flowers were found not to be in the same developmental stages of flowers. Comprehensive analysis revealed that the best harvest stage of chrysanthemum flowers was between the bud stage and the young flower stage (stage 2 and stage 3), which could simultaneously gain the higher contents of active and nutritional ingredients in flowers.

Biochemical traits and proteomic changes in postharvest flowers of medicinal chrysanthemum exposed to enhanced UV-B radiation.

The article studied UV-B effects on biochemical traits and proteomic changes in postharvest flowers of medicinal chrysanthemum. The experiment about UV-B effects on biochemical traits in flowers included six levels of UV-B treatments (0 (UV0), 50 (UV50), 200 (UV200), 400 (UV400), 600 (UV600) and 800 (UV800) µWcm(-2)). UV400, UV600 and UV800 treatments significantly increased the contents of hydrogen peroxide, malondialdehyde and UV-B absorbing compounds, and the activity of phenylalanine ammonia lyase enzyme over the control. The contents of chlorogenic acid and flavone in flowers were significantly increased by UV-B treatments (except for UV50 and UV800). Two-dimensional gel electrophoresis was utilized to analyze proteomic changes in flowers with or without UV-B radiation. Results indicated that 43 protein spots (>1.5-fold difference in volume) were detected, including 19 spots with a decreasing trend and 24 spots with an increasing trend, and 19 differentially expressed protein spots were successfully indentified by MALDI-TOF MS. The indentified proteins were classified based on functions, the most of which were involved in photosynthesis, respiration, protein biosynthesis and degradation and defence. An overall assessment using biochemical and differential proteomic data revealed that UV-B radiation could affect biochemical reaction and promote secondary metabolism processes in postharvest flowers.

Effects of Enhanced UV-B Radiation on Biochemical Traits in Postharvest Flowers of Medicinal Chrysanthemum.

This article reported UV-B radiation effects on biochemical traits in postharvest flowers of chrysanthemum. The experiment included six levels of UV-B radiation (UV0, 0 µW cm(-2); UV50, 50 µW cm(-2); UV200, 200 µW cm(-2); UV400, 400 µW cm(-2); UV600, 600 µW cm(-2) and UV800, 800 µW cm(-2). Enhanced UV-B radiation significantly increased hydrogen peroxide content (except for UV50), but did not evidently affect malondialdehyde content in flowers. Chlorophyll b and total chlorophyll content were significantly increased by UV600 and UV800. UV400 and UV600 significantly increased anthocyanins, carotenoids and UV-B absorbing compounds content, and the activities of phenylalanine ammonia lyase (PAL) and cinnamic acid-4-hydroxylase (C4H) over the control. 4-coumarate CoA ligase (4CL) activity was significantly decreased by enhanced UV-B radiation (except for UV50). The relationships between UV-B radiation intensities and the activities of secondary metabolism enzymes were best described by a second-order polynomial. The R(2) values for UV-B radiation intensities and the activities of PAL, C4H and 4CL were 0.8361, 0.5437 and 0.8025, respectively. The results indicated that enhanced UV-B radiation could promote secondary metabolism processes in postharvest flowers, which might be beneficial for the accumulation of medically active ingredients in medicinal plants. The optimal UV-B radiation intensities in the study were between UV400-UV600.

Two solid-phase recycling method for basic ionic liquid [C4mim]Ac by macroporous resin and ion exchange resin from Schisandra chinensis fruits extract.

In this study, two solid-phase recycling method for basic ionic liquid (IL) 1-butyl-3-methylimidazolium acetate ([C4mim]Ac) were studied through a digestion extraction system of extracting biphenyl cyclooctene lignans from Schisandra chinensis. The RP-HPLC detection method for [C4mim]Ac was established in order to investigate the recovery efficiency of IL. The recycling method of [C4mim]Ac is divided into two steps, the first step was the separation of lignans from the IL solution containing HPD 5000 macroporous resin, the recovery efficiency and purity of [C4mim]Ac achieved were 97.8% and 67.7%, respectively. This method cannot only separate the lignans from [C4mim]Ac solution, also improve the purity of lignans, the absorption rate of lignans in [C4mim]Ac solution was found to be higher (69.2%) than that in ethanol solution (57.7%). The second step was the purification of [C4mim]Ac by the SK1B strong acid ion exchange resin, an [C4mim]Ac recovery efficiency of 55.9% and the purity higher than 90% were achieved. Additionally, [C4mim]Ac as solvent extraction of lignans from S. chinensis was optimized, the hydrolysis temperature was 90°C and the hydrolysis time was 2h.

Enrichment and purification of deoxyschizandrin and γ-schizandrin from the extract of Schisandra chinensis fruit by macroporous resins.

In present study, the performance and separation characteristics of 21 macroporous resins for the enrichment and purification of deoxyschizandrin and γ-schizandrin, the two major lignans from Schisandra chinensis extracts, were evaluated. According to our results, HPD5000, which adsorbs by the molecular tiers model, was the best macroporous resin, offering higher adsorption and desorption capacities and higher adsorption speed for deoxyschizandrin and γ-schizandrin than other resins. Columns packed with HPD5000 resin were used to perform dynamic adsorption and desorption tests to optimize the technical parameters of the separation process. The results showed that the best adsorption time is 4 h, the rate of adsorption is 0.85 mL/min (4 BV/h) and the rate of desorption is 0.43 mL/min (2 BV/h). After elution with 90% ethanol, the purity of deoxy-schizandrin increased 12.62-fold from 0.37% to 4.67%, the purity of γ-schizandrin increased 15.8-fold from 0.65% to 10.27%, and the recovery rate was more than 80%.

Optimization of conditions of solvent-free microwave extraction and study on antioxidant capacity of essential oil from Schisandra chinensis (Turcz.) Baill.

In this article, solvent-free microwave extraction (SFME) of essential oil from Schisandra chinensis (Turcz.) Baill was studied. A multivariate study based on central composite design (CCD) was used to evaluate the influence of three major variables affecting the performance of SFME. The optimum parameters were extraction time 30 min, irradiation power 385 W and moisture content of the fruits was 68%. The extraction yield of essential oil was 11 ml/kg under the optimum conditions. The antioxidant capacity of essential oils extracted by different methods were determined, and compared with traditional antioxidants. GC-MS showed the different composition of essential oil extracted by hydro-distillation (HD), steam-distillation (SD) and SFME. S. chinensis materials treated by different methods were observed by scanning electronic microscopy (SEM) and thermo-gravimetric analysis (TGA). Micrographs and thermo gravimetric loss provided more evidences to prove SFME of essential oil is more completed than HD and SD.

Preparation of high purity biphenyl cyclooctene lignans from Schisandra extract by ion exchange resin catalytic transformation combined with macroporous resin separation.

In this study, ester-bond biphenyl cyclooctene lignans were efficiently hydrolytically degraded into free biphenyl cyclooctene lignans by ion exchange resin transformation and simultaneous removal of impurities by macroporous resin. The OH-type strongly basic anion exchange resin 201×7 was the best one, and the dynamic hydrolysis efficiency was 146.7±5.0%. HPD5000 macroporous resin, which offered higher adsorption and desorption capacities and faster adsorption than other resins. The purity of free biphenyl cyclooctene lignans in the product increased from 5.14±0.24% to 79.67±0.0.67%. After dynamic catalytic transformation by 201×7 resin combined with purification of HPD5000 resin, the yield and the purity of free biphenyl cyclooctene lignans in the product were 132.1±4.7% and 80.91±3.53%, respectively.

Ionic liquid-based microwave-assisted extraction of essential oil and biphenyl cyclooctene lignans from Schisandra chinensis Baill fruits.

Ionic liquid-based microwave-assisted extraction (ILMAE) has been successfully applied in extracting essential oil and four kinds of biphenyl cyclooctene lignans from Schisandra chinensis Baill. 0.25 M 1-lauryl-3-methylimidazolium bromide ionic liquid is selected as solvent. The optimum parameters of dealing with 25.0 g sample are 385 W irradiation power, 40 min microwave extraction time and 1:12 solid-liquid ratio. The yields of essential oil and lignans are 12.12±0.37 ml/kg and 250.2±38.2 mg/kg under the optimum conditions. The composition of the essential oil extracted by hydro-distillation, steam-distillation and ILMAE is analyzed by GC-MS. With ILMAE method, the energy consumption time has not only been shortened to 40 min (hydro-distillation 3.0 h for extracting essential oil and reflux extraction 4.0 h for extracting lignans, respectively), but also the extraction efficiency has been improved (extraction of lignans and distillation of essential oil at the same time) and reduces the environmental pollution. S. chinensis materials treated by different methods are observed by scanning electronic microscopy. Micrographs provide more evidence to prove that ILMAE is a better and faster method. The experimental results also indicate that ILMAE is a simple and efficient technique for sample preparation.

Mangiferin, an anti-HIV-1 agent targeting protease and effective against resistant strains.

The anti-HIV-1 activity of mangiferin was evaluated. Mangiferin can inhibit HIV-1(Ⅲ)(B) induced syncytium formation at non-cytotoxic concentrations, with a 50% effective concentration (EC50) at 16.90 µM and a therapeutic index (TI) above 140. Mangiferin also showed good activities in other laboratory-derived strains, clinically isolated strains and resistant HIV-1 strains. Mechanism studies revealed that mangiferin might inhibit the HIV-1 protease, but is still effective against HIV peptidic protease inhibitor resistant strains. A combination of docking and pharmacophore methods clarified possible binding modes of mangiferin in the HIV-1 protease. The pharmacophore model of mangiferin consists of two hydrogen bond donors and two hydrogen bond acceptors. Compared to pharmacophore features found in commercially available drugs, three pharmacophoric elements matched well and one novel pharmacophore element was observed. Moreover, molecular docking analysis demonstrated that the pharmacophoric elements play important roles in binding HIV-1 protease. Mangiferin is a novel nonpeptidic protease inhibitor with an original structure that represents an effective drug development strategy for combating drug resistance.