Chemical characterization, antioxidant and anti-HIV activities of a Brazilian propolis from Ceará state
Revista Brasileira de Farmacognosia
Propolis (bee glue) a product of Apis mellifera L. is a resinous mixture containing chiefly beeswax and resin harvested by bees from plant leaves, buds and exudates. Extracts of a propolis sample from Salitre, a municipality of Ceará state (northeast Brazil) were obtained with solvents of increasing polarity (hexane, chloroform, ethyl acetate and methanol). A chemical profile was carried out by GC-EI-MS and HPLC-DAD-ESI-MS/MS. Lupenone, lupeol, octanoic acid tetracosyl ester and octanoic acid
... and octanoic acid hexacosyl ester were identified by GC-EI-MS. Antioxidant activity was evaluated by the DPPH and ␤-carotene discoloring methods, and anti-HIV activity by the in vitro inhibition of HIV-1 reverse transcriptase. The ethyl acetate extract exhibited the highest antioxidant and anti-HIV activity and was fractioned by column chromatography using silica gel and seven different eluents. The active fractions were submitted to semi preparative HPLC and the following compounds were isolated: caffeic acid, p-coumaric acid, diprenylcinnamic acid, quercetin, naringenin, isorhamnetin, quercetin-3-O-diglucoside,4,2 ,4trihydroxy-2-methoxychalcone, gossypetin-3,3 ,4 ,7-tetramethyl ether, myricetin-3,7,3 -trimethyl ether and 5-hydroxy-3,6,7,8,4 -pentamethoxyflavone. The ethyl acetate extract and its fractions F5-F7, as well as quercetin, isorhamnetin, myricetin-3,7,3 -trimethyl ether and p-coumaric acid exhibited high antioxidant activity on both DPPH and ␤-carotene antioxidant methods. Isorhamnetin exhibited moderate inhibitory effect against HIV-1 reverse transcriptase (56.99 ± 3.91%), followed by naringenin (44.22 ± 1.71%), quercetin (43.41 ± 4.56%) and diprenylcinnamic acid (41.59 ± 2.59%). These results agree with previous authors who reported anti-HIV activity of flavonoids.