Identification of highly potent α-glucosidase inhibitory and antioxidant constituents from Zizyphus rugosa bark: enzyme kinetic and molecular docking studies with active metabolites

Figures & data

Table 1. α-Glucosidase inhibitory and antioxidant (DPPH) activities of fractions A-G.

	IC50 (mg/mL)
Fraction	Baker’s yeast	Maltase	Sucrase	DPPH
A	0.27 ± 1.41	>1.0	>1.0	>10.0
B	0.19 ± 0.89	>1.0	>1.0	>10.0
C	0.081 ± 0.67	>1.0	>1.0	8.76 ± 1.49
D	0.052 ± 1.23	>1.0	>1.0	2.44 ± 2.16
E	0.094 ± 0.59	>1.0	>1.0	1.47 ± 0.37
F	0.43 ± 1.75	>1.0	>1.0	0.13 ± 0.11
G	0.14 ± 1.22	0.12 ± 0.57	>1.0	0.025 ± 1.85
Acarbose	0.34 ± 1.59	0.0051 ± 0.94	0.0071 ± 2.36	–
Vitamin C	–	–	–	0.028 ± 1.56
BHT	–	–	–	0.072 ± 0.35

Figure 1. Structures of isolated compounds (1-6) from active fractions D and G of Z. rugosa.

Table 2. α-Glucosidase inhibitory and antioxidant (DPPH) activities of 1–6 and 2a–2l.

	IC50 (μM)
Compound	Baker’s yeast	Maltase	Sucrase	DPPH
1	37.2 ± 0.22	>3000	>3000	>10,000
2	16.3 ± 2.03	>3000	>3000	>10,000
3	>600	1480 ± 2.13	2341 ± 1.43	4321 ± 1.13
4	>600	373 ± 1.05	1214 ± 2.01	3795 ± 0.42
5	>600	>3000	>3000	6019 ± 1.36
6	>600	>3000	>3000	42.8 ± 0.83
2a	28.1 ± 0.76	>3000	>3000	>10,000
2b	43.3 ± 0.19	>3000	>3000	>10,000
2c	158 ± 1.22	>3000	>3000	>10,000
2d	269 ± 3.22	>3000	>3000	>10,000
2e	72.1 ± 1.54	>3000	>3000	>10,000
2f	73.1 ± 0.96	>3000	>3000	>10,000
2g	230 ± 0.11	>3000	>3000	>10,000
2h	281 ± 0.89	>3000	>3000	>10,000
2i	368 ± 1.64	>3000	>3000	>10,000
2j	>600	>3000	>3000	>10,000
2k	>600	>3000	>3000	>10,000
2l	>600	>3000	>3000	>10,000
Acarbose	526 ± 1.52	7.9 ± 0.94	10.9 ± 2.36	–
Vitamin C	–	–	–	158 ± 1.90
BHT	–	–	–	328 ± 0.56

Scheme 1. Modified reactions of betunilic acid (2).

Figure 2. Comparison of molecular binding pose of compounds 1 (A) and 2 (B) in yeast α-glucosidase.