Efficacy and safety of Ginkgo biloba extract as an “add-on” treatment to metformin for patients with metabolic syndrome: a pilot clinical study

Figures & data

Figure 1 Flowchart displaying the participant’s screening, randomization, and treatment.

Abbreviations: MTS, metabolic syndrome; GKB, Ginkgo biloba.

Table 1 Baseline characteristics of the randomly allocated MTS patients

Parameters	Met + placebo (n=18)	Met + GKB (n=22)	P-value
Age (years)	47.3±10.8	50.7±7.8	0.25
Male, n (%)	2 (11)	6 (27)	0.54
Weight (kg)	79.8±14.6	88.5±14.6	0.07
BMI (kg/m^2)	34.2±5.6	36.3±4.9	0.22
WC (cm)	102.7±7.6	109.9±8.0	0.07
VAI	203.8±59.4	237.7±81.2	0.15
Insulin resistance	15.1±2.5	16.7±4.1	0.16
MTS duration (years)	3.8±2.1	3.3±2.0	0.35
Metformin therapy
Duration of use (months)	40.1±30.7	30.6±22.7	0.27
Daily dose (g)	1.1±0.5	1.3±0.3	0.37
Biochemical markers
HbA1c (%)	7.2±0.8	7.5±0.8	0.41
FSG (mg/dL)	130.9±24.3	147.0±24.2	0.05
Serum insulin (μU/mL)	22.9±12.2	21.2±8.2	0.61
TG (mg/dL)	157.3±87.1	175.3±85.3	0.39
TC (mg/dL)	185.7±53.2	182.7±34.2	0.83
HDL (mg/dL)	41.8±6.5	39.8±6.3	0.33
LDL (mg/dL)	139.1±32.2	144.5±29.2	0.58

Notes: Values are mean ± SD. GKB: 120 mg GKB extract.

Abbreviations: BMI, body mass index; FSG, fasting blood glucose; GKB, Ginkgo biloba; HbA1c, glycated hemoglobin; HDL, high-density lipoprotein; LDL, low-density lipoprotein; Met, metformin; MTS, metabolic syndrome; TC, total cholesterol; TG, triglyceride; VAI, visceral adiposity index; WC, waist circumference.

Table 2 Glycemic control markers of metabolic syndrome patients maintained on Met and treated with GKB extract

Parameters	Met + placebo (n=18)		Met + GKB (n=22)
	Baseline	90 days	Baseline	90 days
FSG (mg/dL)	130.9±24.3	147.7±45.8	147.0±24.2	129.1±16.1*
HbA1c (%)	7.2±0.8	7.4±0.7	7.5±0.8	6.9±0.7*
Serum insulin (μU/mL)	22.9±27.0^a	22.4±9.7^a	21.2±8.2^a	11.8±5.4*,^b
Insulin resistance	15.1±2.5^a	17.5±4.8*,^b	16.7±4.1^a	13.6±2.9*,^c

Notes: Values were mean ± SD. Values with nonidentical superscripts (a, b, and c) among groups were significantly different (ANOVA, P<0.05). GKB, 120 mg GKB extract.

* Significantly different from baseline in each group (paired t-test, P<0.05).

Abbreviations: FSG, fasting serum glucose; GKB, Ginkgo biloba; HbA1c, glycated hemoglobin; ANOVA, analysis of variance; Met, metformin.

Table 3 Changes in body weight and adiposity markers of metabolic syndrome patients maintained on Met and treated with GKB extract

Parameters	Met + placebo (n=18)		Met + GKB (n=22)
	Baseline	90 days	Baseline	90 days
BMI (kg/m^2)	34.2±5.6	33.7±5.7	36.3±4.9	33.9±5.1*
WC (cm)	102.7±7.6	105.1±8.4*	109.9±8.0	106.7±7.0*
VAI	203.8±59.4	210.8±48.6	237.7±81.2	182.6±74.7*
Serum leptin (ng/mL)	7.9±1.7^a	6.7±2.1^a	8.3±1.1^a	4.7±0.6*,^b

Notes: Values are mean ± SD. GKB, 120 mg GKB extract. Values with nonidentical superscripts (a and b) among groups are significantly different (ANOVA, P<0.05).

* Significantly different from baseline in each group (paired t-test, P<0.05).

Abbreviations: ANOVA, analysis of variance; BMI, body mass index; GKB, Ginkgo biloba; Met, metformin; VAI, visceral adiposity index; WC, waist circumference.

Table 4 Changes in the lipid profile of metabolic syndrome patients maintained on Met and treated with GKB extract

Parameters	Met + placebo (n=18)		Met + GKB (n=22)
	Baseline	90 days	Baseline	90 days
TG (mg/dL)	151.3±87.1	159.9±67.6	175.3±85.3	161.9±73.5
TC (mg/dL)	185.7±53.2	193.7±36.6	182.7±34.2	167.8±31.6^*
LDL (mg/dL)	139.1±32.2	143.9±32.1	144.5±29.2	128.0±28.6^*
HDL (mg/dL)	41.8±6.5	41.3±5.7	39.8±6.3	46.5±8.9^*

Notes: Values are mean ± SD. GKB, 120 mg GKB extract. ^*Significantly different from baseline in each group (paired t-test, P<0.05).

Abbreviations: GKB, Ginkgo biloba; HDL, high-density lipoprotein; LDL, low-density lipoprotein; Met, metformin; TC, total cholesterol; TG, triglyceride.

Table 5 Changes in the inflammatory markers of metabolic syndrome patients maintained on Met and treated with GKB extract

Parameters	Met + placebo (n=18)		Met + GKB (n=22)
	Baseline	90 days	Baseline	90 days
hsCRP (mg/L)	5.9±6.2	6.0±6.1	7.8±5.0	6.2±4.2*
TNF-α (pg/mL)	117.0±57.0^a	113.4±50.1^a	107.6±41.9^a	56.5±34.8*,^b
IL-6 (pg/mL)	27.8±1.7	32.1±26.1	31.3±20.5	19.8±12.1*

Notes: Values are mean ± SD. GKB: 120 mg GKB extract. Values with nonidentical superscripts (a and b) among groups are significantly different (ANOVA, P<0.05).

* Significantly different from baseline in each group (paired t-test, P<0.05).

Abbreviations: ANOVA, analysis of variance; GKB, Ginkgo biloba; hsCRP, high sensitive C-reactive protein; IL-6, interleukin-6; Met, metformin; TNF-α, tumor necrosis factor-α.

Table 6 Changes in the liver and kidney function markers of metabolic syndrome patients maintained on Met and treated with GKB extract

Parameters	Met + placebo (n=18)		Met + GKB (n=22)
	Baseline	90 days	Baseline	90 days
GOT (U/L)	19.1±6.7	18.3±5.2	19.2±5.7	20.6±4.1
GPT (U/L)	18.5±7.2	17.4±5.9	17.7±5.9	17.9±4.9
ALP (U/L)	80.2±23.6	70.8±20.5	90.0±9.1	82.6±14.5*
Serum urea (mg/dL)	25.0±6.3	26.5±9.5	30.1±8.0	25.4±7.9*
Serum creatinine (mg/L)	0.64±0.1	0.73±0.1*	0.73±0.2	0.65±0.1

Notes: Values are mean ± SD. GKB, 120 mg GKB extract.

* Significantly different from baseline in each group (paired t-test, P<0.05).

Abbreviations: ALP, alkaline phosphatase; GKB, Ginkgo biloba; GOT, glutamic–oxaloacetic transaminase; GPT, glutamic–pyruvic transaminase; Met, metformin.

Table 7 Changes in the hematological parameters of metabolic syndrome patients maintained on Met and treated with GKB extract

Parameters	Met + placebo (n=18)		Met + GKB (n=22)
	Baseline	90 days	Baseline	90 days
Hb (g/dL)	12.9±1.1	13.3±1.4	12.3±1.6	14.0±1.7*
Hct (%)	38.1±3.5	40.5±8.5	38.0±5.5	42.1±5.8*
RBC (×10^9 cells/L)	4.6±0.6	4.7±0.5	4.8±0.5	5.2±0.5*
WBC (×10^6 cells/L)	8.6±2.5	7.9±1.8	8.2±2.1	7.9±2.7
Platelet (×10^9 cells/L)	244±51	212±60*	227±47	235±57

Notes: Values are mean ± SD. GKB, 120 mg GKB extract.

* Significantly different from baseline in each group (paired t-test, P<0.05).

Abbreviations: GKB, Ginkgo biloba; Hb, hemoglobin; Hct, hematocrit; Met, metformin; RBC, red blood cell; WBC, white blood cell.