Screening and Bioguided Fractionation of Mimosa pigra L. Bee Pollen with Antioxidant and Anti-Tyrosinase Activities

• Published in: Journal of Apicultural Science 2021-06, Vol.65 (1), p.71-83
• Main Authors: Khongkarat, Phanthiwa, Ramadhan, Rico, Phuwapraisirisan, Preecha, Chanchao, Chanpen
• Format: Article
• Language: English
• Subjects: Antioxidants; bee pollen; Bees; Biogeography; Chromatography; Column chromatography; Dichloromethane; Flavonoids; Flowers; Fractionation; Hexanes; Kojic acid; mimosa; Mimosa pigra; Mushrooms; Naringenin; NMR; Nuclear magnetic resonance; partitioned extract; Pollen; Silica; Silica gel; Silicon dioxide; Size exclusion chromatography; Tyrosinase
• ISSN: 2299-4831; 1643-4439; 2299-4831
• DOI: 10.2478/jas-2021-0001

Bee pollen, one of the economic bee products, is widely known as a nutritional food with many bioactivities that depend on many such factors as bee species, plant source and biogeography. For this study, bee pollen was collected from , harvested from the flowers of mimosa ( L.) in the Chiang Mai province, Thailand. The sample was extracted in methanol (MeOH) and then sequentially partitioned with hexane, dichloromethane (DCM) and MeOH in order to isolate compounds depending on their polarities. The obtained extracts were then tested for their antioxidant and anti-tyrosinase activities through 1,1-diphyenyl-2-picrylhydrazyl (DPPH) assay and for/through inhibition of mushroom tyrosinase extract, respectively. The DCM partitioned extract of mimosa flower bee pollen (DCMMBP) provided the highest antioxidant activity, with an effective concentration at 50% (EC ) of 192.1 μg/mL, and was further fractionated by silica gel 60 column chromatography and Sephadex LH20 size exclusion chromatography. All fractions were tested for their antioxidant activity and analyzed for the chemical structure through nuclear magnetic resonance (NMR). The most active fraction (EC of 121.3 μg/mL) was a mixture of compounds, but the isolated flavonoid, naringenin, had a negligible antioxidant activity. In contrast, all three partitioned extracts and pooled fractions after silica gel 60 column chromatography provided no anti-tyrosinase activity (IC of > 500 μg/mL) and a very low percentage of tyrosinase inhibition (0–2.99 ± 3.18%), compared to kojic acid (IC of 8.58 μg/mL and tyrosinase inhibition of 74.2 ± 1.25%).