Inhibitory effect of Terminalia chebula Retz. fruit extracts on digestive enzyme related to diabetes and oxidative stress

Figures & data

Table 1.  TPC content and HPLC analysis of individual phenolic compounds in ethyl acetate, methanol and 70% methanol–water extracts of T. chebula.

Extract	TPC (mg g^−1 GAE)	Chebulagic acid (mg g^−1)	Chebulinic acid (mg g^−1)	Corilagin (mg g^−1)	Gallic acid (mg g^−1)
TC-2	718.8 ± 25	242.8 ± 6.03	358.6 ± 8.6	24.8 ± 0.58	36.8 ± 1.2
TC-3	623.8 ± 14	159.0 ± 5.8	233.9 ± 3.4	26.2 ± 0.62	5.5 ± 0.14
TC-4	460.8 ± 8	127.2 ± 7.3	99.4 ± 0.98	49.6 ± 2.3	7.7 ± 0.88

GAE-gallic acid equivalent.

Table 2.  α-glucosidase inhibitory effect and antioxidant activity of different extracts of T. chebula on in vitro models, as expressed (µg mL⁻¹) by inhibitory concentration (IC₅₀). Each value represents the mean ± SD of three replicates.

Assay	IC50(µg mL^−1)
	TC-2	TC-3	TC-4
α-Glucosidase inhibition	0.19 ± 0.03	0.28 ± 0.02	1.81 ± 0.10
DPPH	2.01 ± 0.08	3.91 ± 0.05	3.99 ± 0.10
ABTS	2.52 ± 0.09	4.65 ± 0.08	4.52 ± 0.10
Superoxide scavenging	7.03 ± 0.33	12.51 ± 1.2	8.25 ± 0.65

Figure 1.  Dose–response curve for the inhibitory effect of T. chebula extracts on the activity of α-glucosidase.

Figure 2.  DPPH radical scavenging activity of T. chebula extracts. The values were expressed as ±SD of triplicate measurements.

Figure 3.  ABTS radical cation decolourization assay of T. chebula extracts along with the reference compounds trolox and ascorbic acid. All values were represented as ± SD of three parallel measurements (p ≤ 0.05).

Figure 4.  Superoxide radical scavenging activity of extracts and reference compound catechin.

Figure 5.  Effect of TC-2 extract treatment on the intracellular SODs activity in HepG2 cells. Cells were treated with indicated concentrations of the extract for 2 h. Data were expressed as mean ± SD of triplicate experiments.

Figure 6.  Level of total glutathione S-transferase (GST) after treatment of HepG2 cells with TC-2 extract for 24 h. The results are expressed relative to the control and represent mean values ± SD of GST measurements (n = 3).

Figure 7.  Evaluation of oxidative stress in C2C12 cell lines by flow cytometry. Blank – cells without any treatment; control – cells treated with hydrogen peroxide; A – cells treated with hydrogen peroxide and ascorbic acid (25 µg mL⁻¹); others are cells treated with hydrogen peroxide and different concentrations (10, 20, 40, 80 and 100 µg mL⁻¹) of TC-2 extract. Values are represented as mean value ± SD (n = 3).