Picrasidine J, a Dimeric β-Carboline-Type Alkaloid from Picrasma quassioides, Inhibits Metastasis of Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) are associated with recurrence, distant metastasis, and poor overall survival. This highlights the need for identifying potential therapeutics with minimal side-effects. The present study was designed to investigate the anticancer effects of picrasidine J, a dimeric β-carboline-type alkaloid isolated from the southern Asian plant Picrasma quassioides. The results showed that picrasidine J significantly inhibits HNSCC cell motility, migration, and invasion. Specifically, picrasidine J inhibited the EMT process by upregulating E-cadherin and ZO-1 and downregulating beta-catenin and Snail. Moreover, picrasidine J reduced the expression of the serine protease KLK-10. At the signaling level, the compound reduced the phosphorylation of ERK. All these factors collectively facilitated the inhibition of HNSCC metastasis with picrasidine J. Taken together, the study identifies picrasidine J as a potential anticancer compound of plant origin that might be used clinically to prevent the distant metastasis and progression of HNSCC.

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-β-carboline (T4), and 1-methoxycarbonyl-3-methoxyl-β-carboline (T5), are isolated from P. quassioides using the bioassay-guided method. This is the first report of 1-methoxycarbonyl-3-methoxyl-β-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.

Alkaloids from Picrasma quassioides: An overview of their NMR data, biosynthetic pathways and pharmacological effects

Picrasma quassioides, a member of the Simaroubaceae family, is the subject of research in numerous pharmacological and chemical studies. This plant mainly contains alkaloids, quassinoids and terpenoids. These molecules exhibit various pharmacological benefits, such as anti-inflammatory, anticancer, and anti-viral effects, on the cardiovascular system. Alkaloids make up the majority of these molecules. This review describes 127 alkaloid substances from P. quassioides. These alkaloids can be divided into the following classes: β-carbolines, canthinones and alkaloid dimers. A compilation of their nuclear magnetic resonance spectroscopy data and possible biosynthetic pathways of these compounds and the pharmacological effects of P. quassioides are also included.

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.

Don) Benn

Seven undescribed tirucallane-type triterpenoids, kumunorquassins A‒E and kumuquassins K and L, along with nine known analogues, have been isolated from the leaves of Picrasma quassioides (D. Don) Benn. Their structures and absolute configurations were elucidated based on comprehensive spectroscopic analyses, single-crystal X-ray diffraction analysis and electronic circular dichroism (ECD). The absolute configuration of cornusalterin J was unequivocally determined by X-ray diffraction based on its p-bromobenzoate derivative. A brief approach was presented in our study, which could rapidly and conveniently determine the relative and absolute configurations of OCH₃-23 of kumuquassin L and cornusalterins J, H and G depending on the chemical shift differences (Δδ) of C-24 and C-25 and the chemical shifts of C-23, H-23 and H-24. In addition, the cytotoxicities of these compounds against two human tumour cell lines (HepG2 and Hep3B) were evaluated.

The identification of alkaloids from the stems of Picrasma quassioides via computer-assisted structure elucidation and quantum chemical calculations

Four new alkaloids (1-4) and one known alkaloid were isolated from the stems of Picrasma quassioides. The structures of these isolated compounds were elucidated by spectroscopic analyses, a combination of computer-assisted structure elucidation software (ACD/Structure Elucidator) and gauge-including atomic orbital (GIAO) calculation of 1 D NMR data. All compounds were evaluated for their cytotoxic activities against hepatocellular carcinoma HepG2 and Hep3B cells. However, they did not show obvious inhibitory activities.[Figure: see text].

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, β-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.

in the treatment of colitis induced by 2,4,6-trinitrobenzene sulfonic acid in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Picrasma quassiodes (D. Don) Benn.(PQB) is used in folk medicines for the treatment of colds, upper respiratory infection, acute tonsillitis, acute gastroenteritis, bacillary dysentery and a variety of acute infectious diseases in Asia. Although recent reports indicate that PQB has antibacterial, and anti-inflammatory effects, its effects on colitis and its inhibitory mechanisms have not been previously reported.

AIM OF THE STUDY

To assess the effects and the mode of action of the extract of Picrasma quassiodes (D. Don) Benn.(PQB) on a model of colitis in mice induced by trinitrobenzene sulfonic acid (TNBS).

MATERIALS AND METHODS

We induced mice colitis using TNBS/ethanol, then different doses of Picrasma quassiodes (D. Don) Benn.(PQB) extract (100, 200 and 400 mg/kg/day) and sulfasalazine (500 mg/kg/day) were administered by gavage for 7 days after the induction of colitis. The mice body weight, colonic wet weight, colonic lengths, myeloperoxidase (MPO) activity, macroscopic and histological colon injury were observed. Pro-inflammatory cytokines such as: tumor necrosis factor-alpha (TNF-α) and interleukin-8 (IL-8) were assayed by enzyme-linked immunoassay. The protein expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in the colons were determined by immunohistochemical analysis.

RESULTS

PQB administration effectively prevented mice diarrhea, decreasing of the body weights, shortening of colon length and increasing of colon wet weight. Macroscopic and histological examinations also indicated that it was protected against colonic edema, ulceration and MPO activity elevation. Furthermore, PQB inhibited the abnormal secretions of pro-inflammatory cytokines, such as TNF-α and IL-8. Additionally, administration of PQB effectively inhibited COX-2 and iNOS protein expression.

CONCLUSIONS

These results suggest that PQB has an anti-inflammatory effect on TNBS-induced colitis due to the down-regulations of the productions and expressions of inflammatory mediators, and that it may be a potential inflammatory bowel disease (IBD) drug candidate.

Isolation and in vitro antimalarial activity of hexane extract from Thai Picrasma javanica B1 stembark

The in vitro antimalarial activities against Plasmodium falciparum K1 of four extracts from the stembark of Picrasma javanica B1; ie water, methanol, chloroform and hexane extracts were studied using a modification of the [3H]hypoxanthine incorporation method. It was found that the hexane extract showed in vitro antimalarial activity with IC50 of 3.3 microg/ml. The extract was further fractionated using quick column chromatography, resulting in ten fractions. Fraction V was the most effective against P. falciparum K1 with IC50 of 4.4 microg/ml. Further isolation of fraction V using a column chromatographic technique provided six fractions. According to 1H- and 13C-NMR spectra, it could be concluded that the major compound in fraction V-3 was beta-sitosterol. Unfortunately, the antimalarial activity of beta-sitosterol could not be determined because of its low solubility in DMSO. However, fractions V-2 and V-4 still showed in vitro antimalarial activities with IC50 of 2.8 and 3.4 microg/ml, respectively. The further fractionation of these two active fractions could lead to promising candidates as antimalarial agents.