Anti-Inflammatory and α-Glucosidase Inhibitory Activities of Chemical Constituents from Bruguiera parviflora Leaves

Abstract

Bruguiera parviflora (Rhizophoraceae) is one of the Bruguiera genus-based mangrove plants which has not been investigated for the chemical compositions as well as biological activities so far. The present study was aimed at investigating the phytochemicals as well as anti-inflammatory and α-glucosidase inhibitory activities of B. parviflora leaves. The results showed that the crude extract and its fractions significantly increased the percentage inhibitory activity against α-glucosidase and decreased NO production in LPS-stimulated RAW 264.7 cells in a dose-dependent manner. The most effective fraction BP5 was further chromatographed and purified. As a result, eight compounds were isolated and elucidated, including five flavonoids (1–5) and three triterpenoids (6–8). All isolated compounds were evaluated for the anti-inflammatory and α-glucosidase inhibitory effects. The results indicated that flavonoids namely taxifolin (1), quercetin (2), myricetin (3), rutin (4), and kaempferol (5) exhibited potent anti-inflammatory as well as α-glucosidase inhibitory activities. Among them, compound 2 showed the most potent inhibitory effect against an α-glucosidase activity with an I C 50 value of 3.4 ± 0.5 μ g / mL and the LPS-induced NO production of 11.8 μM at the concentration of 100 μg/mL. These findings suggest that flavonoids (1–5) from B. parviflora leaves may be useful as the potential α-glucosidase inhibitor as well as anti-inflammatory agent.

Flavonoids as dual-target inhibitors against α-glucosidase and α-amylase: a systematic review of in vitro studies

“…Taxifolin (also called dihydroquercetin, 24 ) was reported in six studies for its potency to inhibit both α-glucosidase and α-amylase [ 65 , 75 – 79 ]. The results showed that this compound exhibited comparable inhibitory activity to that of acarbose in the same condition while inhibiting α-amylase more weakly.…”

“…Quercetin (68) is a natural polyphenol obtained in more than 50 plant species, as shown in the curated dataset. In terms of α-glucosidase inhibitory potential, quercetin showed superior efficacy compared to acarbose, as demonstrated by 45 out of 65 in vitro studies [ 41 , 51 , 52 , 54 , 61 , 75 , 76 , 83 , 93 – 95 , 98 , 101 , 105 , 114 , 116 , 141 – 169 ], making it the most well-examined flavonoid against α-glucosidase. It is worth mentioning that quercetin ( 68 ) was even used as a positive control in several studies.…”

“…Myricetin (70) displayed similar inhibitory features to those of the previously mentioned aglycones quercetin (68) and kaempferol (69) . As one of the major flavonols found in nature, myricetin is also well-known for its ability to inhibit α-glucosidase [ 49 , 52 , 61 , 65 , 75 , 141 , 143 , 153 , 165 , 169 , 171 , 179 – 183 ]. The IC 50 value on α-glucosidase of myricetin (70) ranged from 0.52 to 3000 µM, as reported in 19 included papers, in which 15 research revealed superior inhibitory effect compared to acarbose in the same experimental condition [ 49 , 52 , 61 , 65 , 75 , 141 , 143 , 153 , 165 , 169 , 171 , 179 – 183 ].…”

“…As one of the major flavonols found in nature, myricetin is also well-known for its ability to inhibit α-glucosidase [ 49 , 52 , 61 , 65 , 75 , 141 , 143 , 153 , 165 , 169 , 171 , 179 – 183 ]. The IC 50 value on α-glucosidase of myricetin (70) ranged from 0.52 to 3000 µM, as reported in 19 included papers, in which 15 research revealed superior inhibitory effect compared to acarbose in the same experimental condition [ 49 , 52 , 61 , 65 , 75 , 141 , 143 , 153 , 165 , 169 , 171 , 179 – 183 ]. Additionally, while α-glucosidase inhibitory mechanisms were discordantly suggested, the inhibition of α-amylase was stated competitively.…”

“…Next is a series of flavonoid glycosides (97–115) , each possessing a sugar residue at C 3 . Several SAR studies have shown that the attachment of sugar moieties diminished the α-glucosidase inhibitory effects of the flavonoids [ 41 , 52 , 61 , 65 , 75 , 93 , 101 , 139 , 141 , 169 , 171 , 180 ]. Moreover, it was suggested that the 3-hydroxyl group in the C ring was essential for proper binding orientation [ 101 ].…”