In vitro alpha glucosidase inhibition and free-radical scavenging activity of propolis from Thai stingless bees in mangosteen orchard

ABSTRACTThe chemical component and biological activity of propolis depend on flora area of bee collection and bee species. In the study, the propolis from three stingless bee species, Lepidotrigona ventralis Smith, Lepidotrigona terminata Smith, and Tetragonula pagdeni Schwarz, was collected in the same region of mangosteen garden from Thailand. Total phenolic content, alpha glucosidase inhibitory effect, and free-radical scavenging activity using FRAP, ABTS, DPPH assays were determined. The most potent activity of propolis extract was investigated for bioactive compounds and their quantity. The ethanol extract of T. pagdeni propolis had the highest total phenolic content 12.83 ± 0.72 g of gallic acid equivalents in 100 g of the extract, and the strongest alpha glucosidase inhibitory effect with the IC50 of 70.79 ± 6.44 µg/ml. The free-radical scavenging activity evaluated by FRAP, ABTS, DPPH assays showed the FRAP value of 279.70 ± 20.55 µmol FeSO4 equivalent/g extract and the IC50 of 59.52 ± 10.76 and 122.71 ± 11.76 µg/ml, respectively. Gamma- and alpha-mangostin from T. pagdeni propolis extract were isolated and determined for the biological activity. Gamma-mangostin exhibited the strongest activity for both alpha glucosidase inhibitory effect and free-radical scavenging activity. Using HPLC quantitative analysis method, the content of gamma- and alpha-mangostin in the extract was found to be 0.94 ± 0.01 and 2.77 ± 0.08% (w/w), respectively. These findings suggested that T. pagdeni propolis may be used as a more suitable raw material for nutraceutical and pharmaceutical products and these mangostin derivatives as markers

Simultaneous HPLC quantitative analysis of mangostin derivatives in Tetragonula pagdeni propolis extracts

Propolis has been used as indigenous medicine for curing numerous maladies. The one that is of ethnopharmacological use is stingless bee propolis from Tetragonula pagdeni. A simultaneous high-performance liquid chromatography (HPLC) investigation was developed and validated to determine the contents of bioactive compounds: 3-isomangostin, gamma-mangostin, beta-mangostin, and alpha-mangostin. HPLC analysis was effectively performed using a Hypersil BDS C18 column, with the gradient elution of methanol–0.2% formic acid and a flow rate of 1 ml/min, at 25 °C and detected at 245 nm. Parameters for the validation included accuracy, precision, linearity, and limits of quantitation and detection. The developed HPLC technique was precise, with lower than 2% relative standard deviation. The recovery values of 3-isomangostin, gamma-mangostin, beta-mangostin, and alpha-mangostin in the extracts were 99.98%, 99.97%, 98.98% and 99.19%, respectively. The average contents of these mixtures in the propolis extracts collected from different seasons were 0.127%, 1.008%, 0.323% and 2.703% (w/w), respectively. The developed HPLC technique was suitable and practical for the simultaneous analysis of these mangostin derivatives in T. pagdeni propolis and would be a valuable guidance for the standardization of its pharmaceutical products

In vitro alpha glucosidase inhibition and free-radical scavenging activity of propolis from Thai stingless bees in mangosteen orchard

Revista Brasileira de Farmacognosia 25 (2015) [445][446][447][448][449][450] w w w . s b f g n o s i a . o r g . b r / r e v i s t a Original Article In vitro alpha glucosidase inhibition and free-radical scavenging activity of propolis from Thai stingless bees in mangosteen orchard a b s t r a c t The chemical component and biological activity of propolis depend on flora area of bee collection and bee species. In the study, the propolis from three stingless bee species, Lepidotrigona ventralis Smith, Lepidotrigona terminata Smith, and Tetragonula pagdeni Schwarz, was collected in the same region of mangosteen garden from Thailand. Total phenolic content, alpha glucosidase inhibitory effect, and freeradical scavenging activity using FRAP, ABTS, DPPH assays were determined. The most potent activity of propolis extract was investigated for bioactive compounds and their quantity. The ethanol extract of T. pagdeni propolis had the highest total phenolic content 12.83 ± 0.72 g of gallic acid equivalents in 100 g of the extract, and the strongest alpha glucosidase inhibitory effect with the IC 50 of 70.79 ± 6.44 g/ml. The free-radical scavenging activity evaluated by FRAP, ABTS, DPPH assays showed the FRAP value of 279.70 ± 20.55 mol FeSO 4 equivalent/g extract and the IC 50 of 59.52 ± 10.76 and 122.71 ± 11.76 g/ml, respectively. Gamma-and alpha-mangostin from T. pagdeni propolis extract were isolated and determined for the biological activity. Gamma-mangostin exhibited the strongest activity for both alpha glucosidase inhibitory effect and free-radical scavenging activity. Using HPLC quantitative analysis method, the content of gamma-and alpha-mangostin in the extract was found to be 0.94 ± 0.01 and 2.77 ± 0.08% (w/w), respectively. These findings suggested that T. pagdeni propolis may be used as a more suitable raw material for nutraceutical and pharmaceutical products and these mangostin derivatives as markers