Quantitative Determination of Principal Aporphine and Benzylisoquinoline Alkaloids Due to Blooming State in Lotus Flower (Flower Buds of Nelumbo nucifera) and Their Hyaluronidase Inhibitory Activity

Abstract

Using a recently developed analytical protocol, distributions of 5 aporphine alkaloids, nuciferine (1), nornuciferine (2), N-methylasimilobine (3), asimilobine (4), and pronuciferine (5), and 5 benzylisoquinoline alkaloids, armepavine (6), norarmepavine (7), N-methylcoclaurine (8), coclaurine (9), and norjuziphine (10), in lotus flowers (the flower buds of Nelumbo nucifera) were analyzed. The flowers were collected at different blooming states (beginning of blooming, one-third in bloom, half in bloom, three-quarters in bloom, and in full bloom) from Saga prefecture, Japan (NN-S1–5). The samples from the beginning of blooming state (NN-S1, 16.35 mg/g in dried material) were found to possess the richest total alkaloid content (1-10). The samples of half in bloom (NN-S3, 52.69 mg per flower of dried material) had the highest total alkaloid content per flower. Among the alkaloid constituents, nornuciferine (2, IC50 = 22.5 µM), asimilobine (4, 11.7 μM), norarmepavine (7, 26.4 μM), coclaurine (9, 11.4 μM), and norjuziphine (10, 24.3 μM) exhibited hyaluronidase inhibitory activity, which was more potent than that of the antiallergic medicine disodium cromoglycate (DSCG, 64.8 μM).