Immature T. chebula fruit extracts high in tannins are thought to be effective in enhancing the wound healing process, according to Li et al., who found in 2011 that the extracts promoted wound healing in rats, likely due to the antibacterial and angiogenic potency of its tannins.1
In a 2014 study on wound healing, Singh et al. observed in vitro that T. chebula extracts effectively scavenged free radicals in a DPPH assay and enhanced proliferation of keratinocytes and fibroblasts. They concluded that T. chebula can be considered for use as a bioactive approach to wound healing for its effects in promoting cellular proliferation and inhibiting production of free radicals.7
Other biologic activities
A 1995 study by Kurokawa et al. showed that T. chebula was one of four herbal extracts among 10 tested to exhibit a discrete anti–herpes simplex virus type 1 (HSV-1) activity in vitro when combined with acyclovir. Oral administration of the herbs with acyclovir in mice in doses corresponding to human use significantly limited skin lesion development and/or extended mean survival time of infected mice in comparison to any of the herbs or acyclovir used alone.14
Nam et al. used a 2,4-dinitrofluorobenzene (DNFB)-induced mouse model of atopic symptoms in 2011 and found that a T. chebula seed extract attenuated atopic dermatitis symptoms, resulting in a 52% decrease in the immune response and lower eosinophil levels in nearby skin tissue.6
In 2013, Manosroi et al. found that various tannins and one oleanane-type triterpene acid isolated from T. chebula galls displayed strong inhibitory capacity against melanogenesis in mice, with one of the tannins (isoterchebulin) shown to decrease protein levels of tyrosinase, microphthalmia-associated transcription factor, and tyrosine-related protein 1 in mainly a concentration-dependent fashion. Another tannin and several triterpenoids were noted for suppressing 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced inflammation. In addition, constituent phenols manifested strong radical-scavenging activity. In a two-stage carcinogenesis mouse model, the investigators observed that the triterpene acid arjungenin hindered skin tumor promotion after initiation with 7,12-dimethylbenz[a]anthracene (DMBA) and promotion by TPA. Their findings indicate a wide range of biologic activity and potential health benefits associated with T. chebula.15
In a mouse study in 2014, Singh et al. determined that a new antifungal agent, an apigenin ointment containing extract of T. chebula stem, was effective in significantly reducing the fungal burden from the experimentally-induced dermatophyte Trichopython mentagrophytes. They suggested that this agent warrants consideration in clinically treating dermatophytosis in humans.16
Triphala, a traditional combination formulation
Long used in Ayurveda, triphala (the word is derived from the Sanskrit tri, three, and phala, fruits) is an antioxidant-rich herbal formulation that combines the dried fruits of T. chebula, Terminalia bellirica, and Emblica officinalis. Naik et al. observed, in a 2005 in vitro study of the aqueous extract of the fruits of T. chebula, T. bellirica, and E. officinalis, as well as their equiproportional mixture triphala, that T. chebula was the most effective at scavenging free radicals. They noted that triphala appears to synergistically combine the strengths of each of its primary components.17 Subsequent studies have demonstrated that triphala is a strong source of natural antioxidants and exhibits a wide range of beneficial activities, including free radical scavenging, antioxidant, anti-inflammatory, analgesic, antibacterial, antimutagenic, wound healing, antistress, adaptogenic, hypoglycemic, anticancer, chemoprotective, radioprotective, chemopreventive, and wound healing.5,18-21
Extracts of T. chebula also have been combined with those of E. officinalis, T. bellirica, Albizia lebbeck, Piper nigrum, Zingiber officinale, and Piper longum in a polyherbal formulation (Aller-7/NR-A2) that has been found safe for the treatment of allergic rhinitis.22
Conclusion
The use of T. chebula in various traditional medical practices around the world is well established. There is ample evidence supporting multiple biologic properties of this Ayurvedic staple. While it is not a standard ingredient in dermatologic health care in the West, the data support continued research as to how best to incorporate this agent.
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