Antimicrobial, Cytotoxic, and -Glucosidase Inhibitory Activities of Ethanol Extract and Chemical Constituents Isolated from Propolis-In Vitro and Molecular Docking Studies.

The chemical investigation of propolis collected in Binh Dinh province, Vietnam, led to the isolation of nine compounds, including four sesquiterpenes: spathulenol (), 1H,5H-aromandendrane-4,10-diol (), 1,6-dihydroxy-4(15)-eudesmene (), and 1H,5H-aromandendrane-4,10-diol (); three triterpenes: acetyl oleanolic acid (), 3-hydroxytirucalla-8,24-dien-21-oic acid (), and ursolic acid (); and two xanthones: cochinchinone A () and -mangostin (). Sesquiterpens - and triterpene were isolated for the first time from stingless bee propolis. Plants in the and genus were suggested as resin sources of the propolis sample.

Chemical Profile and Antioxidant Capacity of Propolis from , , and Stingless Bee Species in Vietnam.

The present study aimed to analyze and compare the chemical profile and antioxidant capacity of propolis from different bee species and different regions. The chemical profiles of propolis from six stingless bee species (, , , , and ) collected from a total of eight locations in Vietnam were investigated by gas chromatography-mass spectrometry (GC-MS). More than 70 compounds were identified, amongst which phenolic lipids (cardanols, resorcinols and anacardic acids), aromatic acids, triterpenes and xanthones.

New dihydrochromene and xanthone derivatives from Lisotrigona furva propolis.

A new dihydrochromene derivative, named lisofurvin (1) and a xanthone, named dihydrobrasixanthone B (2) together with twenty one known compounds (3-23) were isolated from propolis of the stingless bee Lisotrigona furva. Their chemical structures were determined by means of spectroscopic methods including 1D and 2D NMR, and MS. The chemical constituents are predominantly geranyl(oxy) xanthones and Cratoxylum cochinchinense was suggested as a resin source, besides two other plants Mangifera indica and dammar trees (Dipterocarpaceae).

Phytochemical analysis of Vietnamese propolis produced by the stingless bee Lisotrigona cacciae.

Propolis produced by the stingless bee Lisotrigona cacciae was studied for the first time. Using different chromatographic procedures, a total of eighteen constituents (phenols and triterpenes) were isolated, among which flavane 1, homoisoflavanes 2-4, and xanthones 5 and 6 were new for propolis. Propolis extract was also characterized by gas chromatography/mass spectrometry and other fifteen constituents were identified.

Synthesis of auronol derivatives and their immunostimulating activity.

The first synthesis of alphitonin-4-O-β-D-glucopyranoside (1) was described. Since, the nitrile group, a strong hydrogen bond acceptor with a significant solvation shell, is considered to have capacity comparable to sugar for facilitating the cell membrane permeation of the molecules, several alphitonin-4-O-β-D-glucopyranoside and maesopsin-4-O-β-D-glucopyranoside analogues were prepared by replacing glucopyranose moieties with acetonitrile groups. Immunostimulating activity evaluation on lymphocyte proliferation indicated that the compound 7 with an acetonitrile group at OH-4 of alphitonin had a strong stimulation effect on lymphocyte proliferation.

Facile, protection-free, one-pot synthesis of aureusidin.

A new, reliable, and convenient protection-free one-pot method for the synthesis of aureusidin (1) is described. The present synthetic approach involves the condensation of 4,6-dihydroxybenzofuranone with 3,4-dihydroxybenzaldehyde in the presence of concentrated HCl to afford aureusidin (1) in good yield with high purity. This procedure offers a short and simple route for the preparation of aureusidin (1), a bioactive natural product from several vegetal species, as well as for synthesis of other aurones.