| 摘要: | Tea (Camellia sinensis) pollen is one of the main bee-collected pollen staples in Taiwan. We analyzed the contents of the phenolic compounds (total phenols, flavonoids, free aglycones of flavonoid and phenolic acids) in tea pollen, obtained by aqueous extraction (cold and hot water) or ethanolic extraction (50% EE and 95% EE). The antioxidant activity, capacity of scavenging H2O2, and chelating ability were measured. Nine phenolic compounds, including gallic acid, catechin, methyl gallate, caffeic acid, p-coumaric acid, ferulic acid, rutin, myricetin, and chlorogenic acid, were identified and quantified, while gallic acid (0.69 ± 0.01 to 2.55 ± 0.05 mg/g) was the most abundant. In the four tea pollen extracts, caffeic acid, P-coumaric acid, and ferulic acid presented high concentrations. Methyl gallate, rutin and myricetin were detected only in the ethanolic extracts (50% and 95% ethanolic extracts). Ethanolic extracts contained more phenolic compounds than in aqueous extracts. The total antioxidant activity, as measured by the ABTS (2, 2′-azino-bis-(3-ethylbenzthiazoline- 6-sulfonic acid) method, indicated that the ethanolic extracts had greater antioxidant activities than the aqueous extracts and the 50% ethanolic extract effectively chelated ferrous ions. The cold water extract had the greatest hydrogen peroxide scavenging ability. We believe this is the first report on the content of phenolic compounds, especially free flavonoid aglycones, and phenolic acids from tea pollen. Our findings indicated that tea pollen could be a good nutraceutical and dietary antioxidant supplement. |
