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.

[Identification of different lac with infrared spectrum].

Fourier infrared spectrum was used to differentiate raw lac, bleached las and lac mixed with resin. The results indicate that the infrared spectra of raw lac and lac mixed with resin are similar, so the authors can differentiate them by the following items: (1) the position and the shape of absorbing peak between 3500 and 2500 cm(-1), (2) the difference of the vibration peak at 1700 cm(-1) for C=O, (3) characteristic peak between 1200 and 1400 cm(-1), (4) the number of peaks and the change in the position of peak. But with bleached and graft copolymerization lacs the properties have been changed by chemical processing. Graft copolymerization of lac is made from methyl-acrylic acid-methyl fat by using potassium permanganate as stimulant. Their main differences are: the change of vibration peak of 1700 cm(-1) for C=O, a sharp small peak at 1558 cm(-1), a peak with middle strength at 681 cm(-1), and spliting to two small peaks at 1151 cm(-1). The experiment shows that the method of infrared spectrum is more scientific and effective than traditional method.