New sesquiterpenoids with neuroprotective effects in vitro and in vivo from the Picrasma chinensis.

Three undescribed sesquiterpenes, designed as pichinenoid A-C (1-3), along with nine known ones (4-12) were isolated from the stems and leaves of Picrasma chinensis. The new isolates including their absolute configurations were elucidated based on extensive spectroscopic methods, single crystal X-ray diffraction, and electronic circular dichroism (ECD) experiments, as well as comparison with literature data. Structurally, compounds 1 and 2 are descending sesquiterpenes, while pichinenoid C (3) is a rare sesquiterpene bearing a 2-methylenebut-3-enoic acid moiety at the C-6 side chain. All the isolated compounds were tested for their neuroprotective effects against the H2O2-induced damage on human neuroblastoma SH-SY5Y cells, and most of them showed moderate neuroprotective activity. Especially, compounds 1, 3-5, and 7 showed a potent neuroprotective effect at 25 or 50 µM. Moreover, the neuroprotective effects of compounds 1 and 4 were tested on a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease (PD) mouse model. Results of western blot and immunofluorescence indicated that compound 4 significantly counteract the toxicity of MPTP, and reversed the expression of tyrosine hydroxylase (TH) in substantia nigra (SN) and striatum (ST) of the mouse brain. Interestingly, western blot data suggested compound 4 also enhanced B-cell lymphoma-2 (Bcl-2) and heme oxygenase 1 (HO-1) expressions in the brain tissues from MPTP damaged mouse.

Aromatic glycosides and lignans glycosides with their acetylcholinesterase inhibitory activities from the leaves of Picrasma quassioides.

In this study, eight new natural products were isolated from the leaves of Picrasma quassioides. Spectroscopic techniques were used for the elucidation of their planar structures. Their absolute configurations were elucidated on the basis of electron circular dichroism (ECD) techniques combined with the P/M helicity rule for the 2,3-dihydrobenzofuran chromophore, and saccharide hydrolysis. Cholinesterase inhibitors are often used as Alzheimer's disease inhibitors.Thus, acetylcholinesterase and butyrylcholinesterase inhibitory activity of these eight compounds were tested, and results showed that only compound 6 showed weakly acetylcholinesterase inhibitory activity. In particular, molecular docking was used to illustrate the bindings between compound 6 and the active sites of AChE.

Cytotoxicity of isolated compounds from Picrasma crenata (Vell.) Engl. in animal tumor cell (HTC).

The study aim was to evaluate the cytotoxic activity, using the MTT test [3-(4,5-Dimethilthiazol-2-yl)-2,5-diphenil tetrazolium bromide], from the crude extract of Picrasma crenata (Pau Tenente) and its isolated compounds, quassin and parain, in culture of rat liver tumor cells (HTC). The test was carried out exposing the cells for 24, 48 and 72 hours to concentrations of 5, 10, 50, 100, 200, 300, 400, 500 and 1000 µg of crude extract of Pau Tenente/mL of culture medium and 1, 5, 10, 15, 20, 40, 60, 80 and 100 µg of quassin or parain compounds/mL of culture medium. The absorbances averages results obtained showed that the crude extract did not present cytotoxicity for the HTC cells in all the concentrations and evaluated times. For quassin, the concentrations of 80 and 100 µg/mL were cytotoxic, after 72 hours of treatment. For parain, the concentrations of 1, 5, 20, 40, 60, 80 and 100 µg/mL, in 72 hours, were cytotoxic, revealing a new activity for this compound. Thus, the results demonstrate a first indication of the cytotoxic activity of compounds quassin and parain, adding an important social and economic value to them, and may have application in future research and in pharmaceutical industry.

Enhanced Anti-Rheumatoid Arthritis Activity of Total Alkaloids from Picrasma Quassioides in Collagen-Induced Arthritis Rats by a Targeted Drug Delivery System.

New drug delivery systems have rarely been used in the formulation of traditional Chinese medicine, especially those that are crude active Chinese medicinal ingredients. In the present study, hyaluronic acid decorated lipid-polymer hybrid nanoparticles were used to prepare a targeted drug delivery system (TDDS) for total alkaloid extract from Picrasma quassioides (TAPQ) to improve its targeting property and anti-inflammatory activity. Picrasma quassioides, a common-used traditional Chinese medicine (TCM), containing a series of hydrophobic total alkaloids including ß-carboline and canthin-6-one alkaloids show great anti-inflammatory activity. However, its high toxicity (IC50= 8.088±0.903 µg/ml), poor water solubility (need to dissolve with 0.8% Tween-80) and poor targeting property severely limits its clinical application. Herein, hyaluronic acid (HA) decorated lipid-polymer hybrid nanoparticles loaded with TAPQ (TAPQ-NPs) were designed to overcome above mentioned deficiencies. TAPQ-NPs have good water solubility, strong anti-inflammatory activity and great joint targeting property. The in vitro anti-inflammatory activity assay showed that the efficacy of TAPQ-NPs was significantly higher than TAPQ(P<0.001). Animal experiments showed that the nanoparticles had good joint targeting property and had strong inhibitory activity against collagen-induced arthritis (CIA). These results indicate that the application of this novel targeted drug delivery system in the formulation of traditional Chinese medicine is feasible.

Chemical constituents from the twigs and leaves of Picrasma quassioides.

Two new compounds, including a norsesquiterpenoid, annuionone H (1), and a quassinoid, picraqualide G (2), along with eleven known compounds (3-13), were isolated from the twigs and leaves of Picrasma quassioides. Comprehensive spectroscopic analyses and NMR calculation with DP4+ analysis were used to identify their structures. Moreover, of all these compounds, compound 4 showed a week inhibition rate in the anti-inflammatory screening results against mouse macrophage J774A.1 cell.

ß-Carboline alkaloids from Picrasma quassioides and their 3D-QSAR study on anti-inflammation in LPS-induced RAW 264.7 cells.

Two new ß-carboline alkaloids (1-2), 1-pyrrolidone propionyl-ß-carboline (1) and 1-(3-hydroxy-2-oxopiperidine-1-ethyl)-4,8-dimethoxyl-ß-carboline (2), named kumujantine W and J respectively, together with ten known compounds (3-12) were isolated from the stems of Picrasma quassioides (D. Don) Benn. Their structures were elucidated from spectral data including 1D and 2D NMR, UV, IR, HR-ESI-MS spectroscopic analysis and ECD calculations as well as by comparison to the reference databases or literature. The anti-inflammatory effects of these alkaloids (1-12) and six other ß-carboline alkaloids (13-18) in LPS-induced RAW 264.7 cells were evaluated by measuring nitric oxide (NO) concentrations. Among them, compounds 1, 3, 6, 15, and 17 could inhibit the secretion of NO, displaying significant anti-inflammatory activity without affecting cell viability in vitro, and 3D-QSAR analysis further revealed the influence of groups on the activity in ß-carboline alkaloids.

Chemical Constituents of the Branches and Leaves of Picrasma chinensis P.Y. Chen and Tyrosinase Inhibiting Activity.

One new alkaloid, picrasine A, two new quassinoids, picralactones A-B, together with eleven known compounds were isolated from Picrasma chinensis P.Y. Chen. The structures of these compounds were determined using 1D and 2D NMR, HR-ESI-MS, and IR spectroscopic data, and by comparison with published data. Some compounds were tested for tyrosinase inhibiting activity, however, none of them exhibited strong inhibitory effects.

Research on Anti-inflammatory Targets and Mechanisms of alkaloids in Picrasma quassioides Benn Through Network Pharmacology

Abstract This study aimed to investigate the molecular mechanism of Picrasma quassioides Benn against inflammation by means of network pharmacology. The paper will provide a reference for multi-target and multi-channel treatment of inflammation with traditional Chinese medicine. Through screening and analysis, 11 active ingredients and 109 anti-inflammation prediction targets were obtained and constructed a compound-target network. The targets such as VEGFA, TLR4 and STAT3 may play a crucial role. Network enrichment analysis showed that the 109 potential targets constitute a number of pathways or inflammatory reactions closely related to inflammation, including NF-κB signaling pathway and MAPK signaling pathway. The docking results indicated that the binding energy of Picrasidine Y and the inflammatory factors VEGFA is the highest. This study predicted the role of multiple active compounds in the alkaloids of Picrasma in the inflammatory response, and provided a theoretical basis for the anti-inflammatory mechanism of Picrasma

In vivo and in vitro antifungal activities of five alkaloid compounds isolated from Picrasma quassioides (D. Don) Benn against plant pathogenic fungi.

Highly active and novel antifungal compounds are continuously researched from natural products for pesticide development. Picrasma quassioides (D. Don) Benn, a species of Simaroubaceae, is used in traditional Chinese medicine to treat colds and upper respiratory infections. In this study, the active ingredients of P. quassioides and their antifungal activities against plant pathogenic fungi are investigated to explore the practical application of the plant in the agricultural field. The results showed that the extracts of P. quassioides exhibited highly significant preventive and curative effects on apple valsa canker (AVC) with a reduction of lesion diameter were 80.28% and 83.63%, respectively, and can improve the resistance of apple trees to a pathogen. Five antifungal compounds, namely, canthin-6-one (T1), nigakinone (T2), 4,5-dimethoxycanthin-6-one (T3), 1-methoxycarbonyl-ß-carboline (T4), and 1-methoxycarbonyl-3-methoxyl-ß-carboline (T5), are isolated from P. quassioides using the bioassay-guided method. This is the first report of 1-methoxycarbonyl-3-methoxyl-ß-carboline as a natural product. Canthin-6-one shows strong in vitro inhibitory activity against 11 species of plant pathogenic fungi, and their EC50 values range from 1.49 to 8.80 mg/L. The control efficacy of canthin-6-one at 2000 mg/L are 87.88% and 94.37% against AVC and 80.10% and 84.73% against apple anthracnose (C. gloeosporioides), respectively. Additionally, V. mali is observed after treatment with cannin-6-one, although microscopic. This is the first study on the control of the secondary metabolites of P. quassioides against plant fungal diseases. The results show that P. quassioides is a potential resource for the development of botanical fungicides.

Canthin-6-one (CO) from Picrasma quassioides (D.Don) Benn. ameliorates lipopolysaccharide (LPS)-induced astrocyte activation and associated brain endothelial disruption.

BACKGROUND: Canthin-6-one (CO) is an active ingredient found in Picrasma quassioides (D.Don) Benn. (PQ) that displays various biological activities including anti-inflammatory properties. Several studies reported PQ displayed neuroprotective activities, but its effects on astrocytes have not yet been investigated. Astrocytes are crucial regulators of neuroinflammatory responses under pathological conditions in the central nervous system (CNS). Proinflammatory astrocytes can induce the blood-brain barrier (BBB) breakdown, which plays a key role in the progression of neurodegenerative disorder (ND). PURPOSE: This study aims to investigate the anti-neuroinflammatory effects of CO in LPS-induced astrocyte activation and its underlying mechanisms in protecting the blood-brain barrier (BBB) in vitro. METHODS: Mouse astrocytes (C8-D1A) were activated with lipopolysaccharide (LPS) with or without CO pretreatment. Effects of CO on astrocyte cell viability, secretions of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1ß (IL-1ß) and nitric oxide (NO) were determined. Intracellular transcriptions and translations of proinflammatory mediators, molecular signaling, [Ca2+] and the levels of reactive oxygen species (ROS) were evaluated by RT-PCR, western blotting, and flow cytometry, respectively. Astrocyte-conditioned medium (ACM) was further prepared for incubating endothelial monolayer (bEnd.3) grown on transwell. Endothelial disruptions were evaluated by transendothelial electrical resistance (TEER), FITC-dextran permeability and monocyte adhesion assays. Endothelial tight junctions (TJs) and molecular signaling pathways were evaluated by immunofluorescence staining and western blotting. RESULTS: CO attenuated LPS-induced expression of astrocytic proinflammatory mediators (TNF-α, IL-1ß, IL-6, NO) and inhibited deleterious molecular activities including inducible nitric oxide synthase (iNOS), p-NFκB and p-STAT3 in astrocytes. Incubation of ACM collected from CO-treated astrocytes significantly ameliorated endothelial disruptions, reduced expressions of endothelial cytokine receptors (IL-6R, gp130 (IL-6RB), TNFR and IL-1R), suppressed proinflammatory pathways, MAPKs (p-AKT, p-MEK, p-ERK, p-p38, p-JNK) and p-STAT3, restored endothelial stabilizing pathways (p-Rac 1) and upregulated beneficial endothelial nitric oxide synthase (eNOS). CONCLUSION: Our study demonstrates for the first time CO exhibited potent protective effects against astrocyte-mediated proinflammatory responses and associated endothelial barrier disruptions.

Genus Picrasma: A comprehensive review on its ethnopharmacology, phytochemistry and bioactivities.

ETHNOPHARMACOLOGICAL RELEVANCE: The genus Picrasma belongs to the Simaroubaceae family and contains six species which are mainly distributed in tropical and subtropical regions of Asia and America. The barks, roots, stems, branches, or leaves of several Picrasma species have been applied as folk medicines to treat fever, sore throat, dysentery, eczema, nausea, loss of appetite, diabetes mellitus, cancer, and hypertension. AIM OF THE STUDY: A systematic summary on the botanic characterization, ethnopharmacological uses, phytochemistry, bioactivities and toxicity of species belonging to Picrasma was presented to facilitate the exploitation of the therapeutic potential of these plants. MATERIALS AND METHODS: The literatures about Picrasma were retrieved from a series of scientific search engines including Web of Science, SciFinder, PubMed, CNKI, Google Scholar, Elsevier, Wiley, ACS publications, and SpringerLink between 1970 and 2020. Plant names were validated by "The Plant List" (www.theplantlist.org). RESULTS: As ethnopharmacological uses, Picrasma species are valuable folk medicines to treat fever, inflammation, dysentery, eczema, cancer, diabetics, skin infection, and so on. Up to now, a total of 361 compounds including 126 alkaloids, 132 quassinoids, 67 triterpenoids, and 36 miscellaneous compounds were reported from Picrasma species. Quassinoids and alkaloids are the principal constituents in the genus. The extracts and phytochemical constituents of Picrasma species demonstrate a wide range of bioactivities including cytotoxic, anti-inflammatory, antimicrobial, and other activities. CONCLUSIONS: Picrasma species are widely used as traditional medicines, have diverse chemical constituents with obvious biological activities. Nevertheless, further studies are required on the Picrasma species to assert the ethnopharmacological uses, clarify their bioactive constituents, determine pharmacological actions, and toxicity. Therefore, the present review may provide a critical clue for future studies and further exploitations on Picrasma species.

Quassinoids with Inhibitory Activities against Plant Fungal Pathogens from Picrasma javanica.

A bioactivity-guided study on the leaves of Picrasma javanica led to the isolation of 19 quassinoids, including 13 new compounds. The structures of the new compounds were elucidated by a combination of spectroscopic data analysis, X-ray crystallography studies, and electronic circular dichroism (ECD) data interpretation. Compounds 1-7 are rare examples of quassinoids with a keto carbonyl group at C-12. The biological activities of 11 of the more abundant isolates were evaluated against five phytopathogenic fungi in vitro, and several of them including 6 and 15 showed moderate inhibitory effects that were comparative to those of the positive control, carbendazim. In addition, the preliminary structure-activity relationships (SARs) of these quassinoids were also investigated.

Dehydrocrenatidine extracted from Picrasma quassioides induces the apoptosis of nasopharyngeal carcinoma cells through the JNK and ERK signaling pathways.

Nasopharyngeal carcinoma (NPC) is an indicator disease in Asia due to its unique geographical and ethnic distribution. Dehydrocrenatidine (DC) is a ß­carboline alkaloid abundantly present in Picrasma quassioides (D. Don) Benn, a deciduous shrub or small tree native to temperate regions of southern Asia, and ß­carboline alkaloids play anti­inflammatory and antiproliferative roles in various cancers. However, the mechanism and function of DC in human NPC cells remain only partially explored. The present study aimed to examine the cytotoxicity and biochemical role of DC in human NPC cells. The MTT method, cell cycle analysis, DAPI determination, Annexin V/PI double staining, and mitochondrial membrane potential examination were performed to evaluate the effects of DC treatment on human NPC cell lines. In addition, western blotting analysis was used to explore the effect of DC on apoptosis and signaling pathways in related proteins. The analysis results confirmed that DC significantly reduced the viability of NPC cell lines in a dose­ and time­dependent manner and induced apoptosis through internal and external apoptotic pathways (including cell cycle arrest, altered mitochondrial membrane potential, and activated death receptors). Western blot analysis illustrated that DC's effect on related proteins in the mitogen­activated protein kinase pathway can induce apoptosis by enhancing ERK phosphorylation and inhibiting Janus kinase (JNK) phosphorylation. Notably, DC induced apoptosis by affecting the phosphorylation of JNK and ERK, and DC and inhibitors (SP600125 and U0126) in combination restored the overexpression of p­JNK and p­ERK. To date, this is the first study to confirm the apoptosis pathway induced by DC phosphorylation of p­JNK and p­REK in human NPC. On the basis of evidence obtained from this study, DC targeting the inhibition of NPC cell lines may be a promising future strategy for NPC treatment.

Phytochemistry, Traditional Use and Pharmacological Activity of Picrasma quassioides: A Critical Reviews.

Picrasma quassioides is a member of the Simaroubaceae family commonly grown in the regions of Asia, the Himalayas, and India and has been used as a traditional herbal medicine to treat various illnesses such as fever, gastric discomfort, and pediculosis. This study aims to critically review the presence of phytochemicals in P. quassioides and correlate their pharmacological activities with the significance of its use as traditional medicine. Data were collected by reviewing numerous scientific articles from several journal databases on the pharmacological activities of P. quassioides using certain keywords. As a result, approximately 94 phytochemicals extracted from P. quassioides were found to be associated with quassinoids, ß-carbolines and canthinones. These molecules exhibited various pharmacological benefits such as anti-inflammatory, antioxidant, anti-cancer, anti-microbial, and anti-parasitic activities which help to treat different diseases. However, P. quassioides were also found to have several toxicity effects in high doses, although the evidence regarding these effects is limited in proving its safe use and efficacy as herbal medicine. Accordingly, while it can be concluded that P. quassioides may have many potential pharmacological benefits with more phytochemistry discoveries, further research is required to determine its real value in terms of quality, safety, and efficacy of use.

Anti-tumor Properties of Picrasma quassioides Extracts in H-RasG12V Liver Cancer Are Mediated Through ROS-dependent Mitochondrial Dysfunction.

BACKGROUND: Picrasma quassioides (PQ) is a traditional Asian herbal medicine with anti-tumor properties that can inhibit the viability of HepG2 liver cancer cells. H-Ras is often mutated in liver cancer, however, the effect of PQ treatment on H-Ras mutated liver cancer is unclear. This study aimed to investigate the role of PQ on ROS accumulation and mitochondrial dysfunction in H-ras mutated HepG2 (HepG2G12V) cells. MATERIALS AND METHODS: PQ ethanol extract-induced HepG2G12V apoptosis was analyzed by the MTT assay, fluorescence microscopy, flow cytometry and western blotting. RESULTS: PQ treatment affected cell migration and colony formation in HepG2G12V cells. Cleaved-caspase-3, cleaved-caspase-9 and BCL2 associated agonist of cell death (BAD) expression levels were increased, while the levels of B-cell lymphoma-extra large (Bcl-xL) were decreased with PQ treatment. PQ treatment led to a reduction of H-Ras expression levels in liver cancer cells, thus reducing their abnormal proliferation. Furthermore, it led to increased expression levels of Peroxiredoxin VI, which regulates the redox signal in cells. CONCLUSION: Taken together these results provide a new functional significance for the role of PQ in treating HepG2G12V liver cancer.

Picrasma quassioides Extract Elevates the Cervical Cancer Cell Apoptosis Through ROS-Mitochondrial Axis Activated p38 MAPK Signaling Pathway.

BACKGROUND/AIM: Picrasma quassioides (P. quassioides) is used in traditional Asian medicine widely for the treatment of anemopyretic cold, eczema, nausea, loss of appetite, diabetes mellitus, hypertension etc. In this study we aimed to understand the effect of P. quassioides ethanol extract on SiHa cervical cancer cell apoptosis. MATERIALS AND METHODS: The P. quassioides extract-induced apoptosis was analyzed using the MTT assay, fluorescence microscopy, flow cytometry and western blotting. RESULTS: P. quassioides extract induced cellular apoptosis by increasing the accumulation of cellular and mitochondrial reactive oxygen species (ROS) levels and inhibiting ATP synthesis. Pretreatment with N-Acetylcysteine (NAC), a classic antioxidant, decreased the intracellular ROS production and inhibited apoptosis. In addition, the P38 MAPK signaling pathway is a key in the apoptosis of SiHa cells induced by the P. quassioides extract. CONCLUSION: The P. quassioides extract exerts its anti-cancer properties on SiHa cells through ROS-mitochondria axis and P38 MAPK signaling. Our data provide a new insight for P. quassioides as a therapeutic strategy for cervical cancer treatment.

Three new quassinoids isolated from the wood of Picrasma javanica and their anti-Vpr activities.

Three new quassinoids, javanicinols A and B (1 and 2) and 4-keto-(16S)-methoxyjavanicin B (3), together with three known quassinoids (4-6) were isolated from the chloroform-soluble fraction of the methanol extract of the Picrasma javanica wood. The structures of 1-3 were determined by spectroscopic analyses, including 1D and 2D NMR, HRESIMS, and CD. The anti-HIV-1 viral protein R (Vpr) assay revealed that 1 and 2 exhibited potent anti-Vpr activities at 1.25 µM. Furthermore, the assay also revealed the potent anti-Vpr activities of (16R)-methoxyjavanicin B (7) and (16S)-methoxyjavanicin B (8), which were previously isolated from the Picrasma javanica wood.

Pharmacokinetic and bioavailability study of 5-hydroxy-4-methoxycanthin-6-one, a typical canthinone alkaloid, in rats using ultra-high performance liquid chromatography/electrospray ionization tandem mass spectrometry.

5-methoxycanthin-6-one, a major canthinone alkaloid isolated from Picrasma quassioides, exhibited significant pharmacological activities. In this study, a rapid and sensitive LC-MS/MS method was established and validated for the determination of 5-hydroxy-4-methoxycanthin-6-one in rat plasma. Small quantities (20 µL) of plasma sample were used for sample preparation. 5-Hydroxy-4-methoxycanthin-6-one and an internal standard (IS, caffeine) were separated using an ACQUITY HSS T3 column (50 × 2.1 mm, 1.7 µm; Waters, Milford, MA, USA). The mobile phase was composed of 0.1% formic acid in water and acetonitrile. Precursor-to-product ion transitions were m/z 267.0 → 168.2 and m/z 195.0 → 138.1 for quantitative monitoring of 5-hydroxy-4-methoxycanthin-6-one and IS, respectively. The assay was linear over the concentration range of 0.5-500 ng/mL (r > 0.99) with the lower limit of quantification 0.5 ng/mL. Other parameters, including intra- and inter-day precision and accuracy, carryover, stability, extraction recovery, matrix effect, and dilution effect, were within acceptable limits. The validated method was successfully applied to pharmacokinetic study in rats after intravenous (5 mg/kg) and oral (10, 25, 50 mg/kg) administration of 5-hydroxy-4-methoxycanthin-6-one. The result indicated that 5-hydroxy-4-methoxycanthin-6-one was quickly absorbed into the blood and reached the highest concentration at ~33.0-42.0 min, with moderate elimination half-life (0.85-2.11 h) and low bioavailability (16.62-24.42%) after oral administration. The study provided valuable information that can be used as a reference for studying other canthinone alkaloids.

Quassinoids with Insecticidal Activity against Diaphorina citri Kuwayama and Neuroprotective Activities from Picrasma quassioides.

Six new quassinoids, named kumulactone F (1), kumulactone G (2), kumulactone H (4), kumulactone I (5), kumulactone J (6), and kumulactone K (7), a pair of undescribed epimers α- and ß-nigakihemiacetal G (3), 15 known quassinoids (8-22), and a mixture of the known compounds α- and ß-neoquassin (23) were separated from the dried stems of the medical plants Picrasma quassioides. The chemical structures of all of the new compounds were established by spectroscopic data analyses (HR-ESI-MS, 1D and 2D NMR spectroscopy, and electronic circular dichroism (ECD)). Biologically, compounds 9 and 21 showed toxicity toward the Asian citrus psyllid Diaphorina citri Kuwayama with potent activity even equal to that of the positive control (Abamectin), compound 11 exhibited an excellent neuroprotective effect against SH-SY5Y cells which were pretreated by H2O2 with potent activity equal to that of the positive control (Trolox), and none of them showed cytotoxic activity toward the HeLa or A549 cell lines (IC50 > 100 µM).

A pair of new tirucallane triterpenoid epimers from the stems of Picrasma quassioides.

A pair of new tirucallane triterpenoid epimers, picraquassins M and N (1> and 2), were isolated from the stems of Picrasma quassioides (D. Don) Benn. Their structures were determined based on comprehensive spectroscopic and X-ray crystallographic analyses. In addition, their AChE inhibitory activity, cytotoxicity against five human tumour cell lines (SW480, MCF-7, HepG2, Hela, and PANC-1), and antimicrobial activity against two bacteria (Staphylococcus. aureus 209P and Escherichia coli ATCC0111) and two fungi (Candida albicans FIM709 and Aspergillus niger R330) were evaluated.