Chemical constituents from the flowers of Satsuma mandarin and their free radical scavenging and α-glucosidase inhibitory activities

Abstract

Flowers of Citrus plants are used as mild sedatives and for the treatment of insomnia in traditional medicines. In Japan, tea made from the flowers of Satsuma mandarin is consumed as healthy drink. Hesperidin (1), hesperetin (2), rutin (3), quercetin (4), nicotiflorin (5), eriocitrin (6), narirutin (7), phenylethyl glucoside (8) and unshuoside A (9) were isolated from the MeOH extract of fresh flowers. Structure elucidation of these compounds was performed on the basis of NMR spectroscopic data. Among them, rutin (3), quercetin (4) and eriocitrin (6) showed potent free radical scavenging activity, whereas hesperetin (2) and quercetin (4) showed potent α-glucosidase inhibitory activity.

Phytochemical Screening, Free Radical Scavenging and α-Amylase Inhibitory Activities of Selected Medicinal Plants from Western Nepal

“…This result further supports that the antioxidant activity of these plants is in agreement with their total phenolic and flavonoid contents, as stated in previous studies [24,32]. Phenolic compounds and flavonoids with unsubstituted hydroxyl groups have been recognized as potent free radical scavengers [33,34]…”

Flavonoids from the Flowers of Citrus ‘Hebesu’

“…On the basis of these data, the structure of 1 was assigned as 2(S)-3',4'-dimethoxy-5,7dihydroxyflavanone 7-O-neohesperidoside ( Figure 1 Results obtained from this study revealed that the flowers of Citrus 'Hebesu' are rich in flavonoids, which were similar to previous reports on flowers of other Citrus plants. For example, compound 2 was reported previously from the flowers of C. sinensis [1] and C. unshiu [3]. Similarly, compounds 5-7 were also reported from the flowers of C. unshiu [3].…”

“…Previous studies have reported anti-inflammatory activity of 80% ethanol extract of flowers of C. unshiu [4], antioxidative activity of the MeOH extract of flowers of C. grandis 'Tomentosa' [5] and sedative activity of MeOH and CH 2 Cl 2 extracts C. sinensis [1]. Recently, we reported flavonoids with potent free radical scavenging and -glucosidase inhibitory activities and other compounds from the MeOH extract of flowers of Satsuma mandarin (C. unshiu) [3]. Citrus 'Hebesu' is a local cultivar of Citrus plant in Hyuga City of Miyazaki Prefecture, Japan.…”

“…Flowers of Citrus plants (Family: Rutaceae) are used as mild sedatives in traditional medicines [1,2]. In Japan, flowers of C. unshiu are used as healthy tea [3]. Although most of the previous works on flowers of Citrus plants were focused on the constituents and bioactivities of essential oils, there are relatively very few reports on the chemical constituents and biological activities of extracts consisting non-volatile constituents.…”

Anti‐neuroinflammatory activities of extract and polymethoxyflavonoids from immature fruit peels of Citrus ‘Hebesu’

“…Citrus peels are one of the underutilized resources and were considered to be waste products. However, in recent years, Citrus peels and flowers are gaining attraction, as these are reported to contain highly bioactive compounds (Adhikari-Devkota, Elbashir, Watanabe, & Devkota, 2018). Citrus fruits and peels are also used as traditional medicines in different countries for digestive problems, cough, skin inflammation and infection, and muscle pain (Gao, Gao, Zeng, Li, & Liu, 2018;Matsumoto et al, 2017).…”