TY - EJOU
AU - Paul, Swastika
AU - Zhang, Xuemei
AU - Yang, Yongping
AU - Geng, Changan
TI - Chemical Constituents from Turnip and Their Effects on α-Glucosidase
T2 - Phyton-International Journal of Experimental Botany
PY - 2020
VL - 89
IS - 1
SN - 1851-5657
AB - Brassica rapa var. rapa (turnip) is an important crop in Qinghai-Tibet
Plateau (QTP) with anti-hypoxic effect. Turnip is rich in glucosinolates,
isothiocyanates and phenolic compounds with diverse biological activities,
involving anti-oxidant, anti-tumor, anti-diabetic, anti-inflammatory, anti-microbial,
hypolipidemic, cardioprotective, hepatoprotective, nephroprotective and analgesic
properties. In this study, the ethyl acetate (EtOAc) and butanol parts of Brassica
rapa were first revealed with inhibitory effects on α-glucosidase, whereas the water
part was inactive. Subsequent bioassay-guided isolation on the EtOAc and butanol
parts yielded 12 compounds, involving three indole derivatives, indole-3-
acetonitrile (1) 4-methoxyindole-3-acetonitrile (2) and indole-3-aldehyde (3) two
flavonoids, liquiritin (4) and licochalcone A (5) two phenylpropanoids, sinapic acid
(6) and caffeic acid (7) two phenylethanol glycosides, 2-phenylethyl β-
glucopyranoside (8) and salidroside (9) and three other compounds, syringic acid
(10) adenosine (11) and (3β, 20E)-ergosta-5, 20 (22)-dien-3-ol (12) Licochalcone
A (5) and caffeic acid (7) showed α-glucosidase inhibitory activity with IC50 values
of 62.4 ± 8.0 μM and 162.6 ± 3.2 μM, comparable to the positive control, acarbose
(IC50 = 142 ± 0.02 μM). Docking study suggested that licochalcone A (5) could
well align in the active site of α-glucosidase (docking score = -52.88) by forming
hydrogen bonds (Gln1372, Asp1420, Gln1372, Arg1510), hydrophobic effects
(Tyr1251, Tyr1251, Trp1355, Phe1560, Ile1587, Trp1355, Phe1559, Phe1559) and
π-π stacking interaction (Trp1355). This study provides valuable information for
turnip as a new resource in searching anti-diabetic candidates.
KW - Brassica rapa; turnip; α-glucosidase; licochalcone A; docking study
DO - 10.32604/phyton.2020.08328