Combined extracts of Garcinia mangostana fruit rind and Cinnamomum tamala leaf supplementation enhances muscle strength and endurance in resistance trained males

Abstract

Background

A proprietary composition GMCT contains extracts of two popular Asian herbs viz., Garcinia mangostana (GM) fruit rind and Cinnamomum tamala (CT) leaf. We systematically evaluated physical performance and muscle strength enhancing ability of GMCT in a preclinical mouse model followed by a 42-days double-blind placebo controlled human trial in resistance trained adult males.

Methods

Four groups of Swiss albino mice (20–30 g body weight) (n = 6) were fed a standard laboratory diet and given Carboxymethylcellulose sodium (CMC), 150 mg/kg GMCT (GMCT-150), 300 mg/kg GMCT (GMCT-300) or 50 mg/kg Oxymetholone (OXY) via oral gavage for 21 days. On day 22, the animals’ physical performance and muscle strength were assessed in a forced swimming test (FST) and forelimb grip strength experiment, respectively.

In the human trial, thirty-eight resistance-trained young adults (mean age 26.32 ± 4.39 years, body weight 67.79 ± 12.84 kg, BMI 22.92 ± 3.54 kg/m²) completed the trial. The participants received either GMCT (n = 19; 800 mg daily) or matched placebo (n = 19) for 42 days. As primary variables, 1-RM bench press, 1-RM leg press, and leg extension repetitions were measured at baseline and on days 14, 28 and 42 of the intervention. Anthropometric parameters and serum markers such as free testosterone, insulin-like growth factor 1 (IGF-1), insulin and lactate were also measured before and after the intervention.

Results

GMCT-300 mice showed significant improvement in swimming time (GMCT: 395.3 ± 81.70 s vs. CMC: 271.6 ± 56.86 s; p = 0.0166), distance (GMCT: 341.22 ± 65.88 m vs. CMC: 260.84 ± 49.15 m; p = 0.0461) and grip strength (GMCT: 43.92 ± 6.97 N vs. CMC: 35.0 ± 6.92 N; p = 0.0490), compared with the CMC group.

At the end of the 42-day human trial, the per protocol analyses reveal that mean changes from baseline 1-RM bench press (GMCT: 23.47 ± 10.07 kg vs. PL: 3.42 ± 2.06 kg; p < 0.0001), leg press (GMCT: 29.32 ± 16.17 kg vs. PL: 5.21 ± 1.72 kg; p < 0.0001), number of leg extension repetitions (GMCT: 6.58 ± 2.57 vs. PL: 2.05 ± 1.22; p < 0.0001) in GMCT group were significantly improved, compared with placebo. Intergroup difference analyses show that the changes from baseline left arm (GMCT: 1.09 ± 0.36 cm vs. PL: 0.68 ± 0.42 cm; p = 0.0023), right arm (GMCT: 1.50 ± 0.44 cm vs. PL: 1.11 ± 0.43 cm; p = 0.0088) circumference and lean mass (GMCT: 2.29 ± 2.09 kg vs. PL: 0.52 ± 2.58 kg; p = 0.0404) in GMCT group were also significantly improved, compared with placebo. In comparison to placebo, GMCT supplementation did not improve free testosterone, IGF-1, insulin or lactate levels. Parameters of clinical biochemistry, hematology, urine and vital signs of the participants were within the normal range.

Conclusion

GMCT supplementation is effective in increasing muscle strength, muscle size and, total lean mass, as well as endurance performance.

Trial Registration.

Clinical Trial Registry of India (CTRI/2015/01/005374), Registered on Jan 07, 2015; CTRI Website URL - http://ctri.nic.in

Keywords:

• Cinnamomum tamala
• Endurance of exercise
• Forced swim test
• Free testosterone
• Garcinia mangostana
• Lean body mass
• Muscle strength

Acknowledgments

The authors thank Sri. G. Ganga Raju, Chairman, Mr. G. Rama Raju, Director Laila Group and Mr. B. Kiran CEO, Laila Nutraceuticals for encouragement and generous support. The authors also thank B10 Analytics Pvt. Ltd., Thiruvananthapuram, Kerala, India for the data management and analyses, the physical instructors and the subjects who participated in the trial.

Funding

The studies were sponsored by Laila Nutraceuticals, India; no additional funding was received.

Availability of data and materials

Data and publication materials are available upon request.

Authors’ contributions

MRK was the principal investigator and conducted the clinical trial. TG was primarily responsible for standardization and quality assurance of the investigational product. KVA and KS designed the study. PKJ undertook the management of the trial including quality assurance and the data collection. KS interpreted results and wrote the manuscript. All authors critically reviewed the draft and approved the final manuscript.

Ethics approval and consent to participate

The preclinical study protocol was approved by the Institutional Animal Ethics Committee. The ethics approval for the clinical trial was obtained from the ethical committee of Alluri Sitarama Raju Academy of Medical Sciences (ASRAM), Eluru, India, a not for profit organization. All participants signed the Institutional Review Board approved informed consent before the commencement of the study.

Consent for publication

Not applicable.

Competing interests

The research team of the sponsor designed the clinical study protocol. The entire study operation and the data analyses were carried out independently by the Suraksha Health Village (SHV), Vijayawada, India and B10 Analytics Pvt. Ltd. Thiruvananthapuram, India, respectively. SHV is an independent health science center, who independently operated the clinical trial. MRK is an Ayurvedic practitioner and is an employee of SHV. He has no financial interest in conducting the study. KVA, PKJ, TG, and KS are employees of Laila Nutraceuticals R & D Center, India. Laila Nutraceuticals has filed a patent application on GMCT composition (PCT/IN/2014/000004).

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