Terminalia chebula, a member of the Combretaceae family, is an evergreen plant found abundantly in India, Pakistan, China, Thailand, Sri Lanka, and Malaysia.1,2 It has long been used in traditional medicine, particularly Ayurveda, as well as in Thai traditional medicine.3 It also has also been used for many years in the traditional medicine of the Samahni valley of Pakistan to treat chronic ulcers as well as dental caries and heart ailments.4 Other traditional indications include asthma and urinary disorders.5 In Thailand, it has been used to treat skin diseases and to promote wound healing and rejuvenation.1 It is particularly known for its potent antioxidant and antimicrobial properties.6 The wide array of health benefits associated with T. chebula is attributed to its high content of phenolic compounds, flavonol glycosides, and other phytonutrients.7
Antioxidant, anti-aging, and depigmenting effects
In 2004, Na et al. observed that T. chebula fruit extract exerted an inhibitory effect on the age-dependent shortening of telomeres and UVB-induced oxidative damage in vitro.8
Kim et al. screened 50 Korean plants to identify natural sources of elastase and hyaluronidase inhibitors in 2010. The strong efficacy of T. chebula led the investigators to choose it for additional study in which the fruits of the methanol crude extract at 1 mg/mL demonstrated 80% elastase and 87% hyaluronidase inhibitory activities. In addition, the investigators isolated 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (PGG), which also exhibited significant inhibition of elastase and hyaluronidase and induction of type II collagen expression. The authors concluded that PGG has the potential as a cutaneous anti-aging agent posing no cytotoxicity concerns and warrants further in vivo study.9
A 2010 in vitro study of the anti-aging properties of the extracts of 15 plant species, including T. chebula galls, outgrowths that result from insect bites, was conducted by Manosroi et al. The cold aqueous extract of T. chebula manifested the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity and highest stimulation index for proliferation of normal human skin fibroblasts. T. chebula, which also inhibited matrix metalloproteinase (MMP)-2 activity, was compared against compounds such as ascorbic acid, alpha-tocopherol, and butylated hydroxytoluene. The investigators concluded that their findings supported the traditional uses of T. chebula gall in Thai medicine and suggest that T. chebula would be beneficial for inclusion in new anti-aging formulations.3
Later that year, Manosroi et al. characterized the biological activities of the phenolic compounds isolated from T. chebula galls, finding that these compounds (gallic acid, punicalagin, isoterchebulin, 1,3,6-tri-O-galloyl-beta-D-glucopyranose, chebulagic acid, and chebulinic acid) exhibited greater radical-scavenging and melanin-inhibitory activity than the reference compounds ascorbic acid, butylated hydroxytoluene, alpha-tocopherol, arbutin, and kojic acid. Although the T. chebula constituents were less effective than the reference compounds in mushroom tyrosinase inhibition and human tumor cytotoxicity assays, the investigators concluded that the antioxidant and depigmenting activity of the constituents of T. chebula accounted for the beneficial profile of the plant that has emerged over time.10
The next year, Manosroi et al. assessed the cutaneous anti-aging effects of a gel containing niosomes incorporating a semi-purified fraction including gallic acid derived from T. chebula galls or outgrowths. Human volunteers were enlisted to test skin elasticity and roughness and rabbit skin was used to evaluate skin irritation. The gel containing the semi-purified fractions loaded in niosomes was compared with an unloaded fraction, revealing that the loaded niosomes yielded greater gallic acid chemical stability as well as in vivo anti-aging effects.11 Earlier that year, the team had shown the viability of niosomes, particularly elastic ones, to promote chemical stability for the transdermal absorption of gallic acid in semipurified T. chebula gall fractions in rats. Their findings, they concluded, point to the potential for achieving topical anti-aging benefits from such formulations.12
In 2012, Akhtar et al. developed a water-in-oil T. chebula formulation and assessed its effects on various parameters. The investigators prepared a base with no active ingredients and a 5% T. chebula formulation, which remained stable at various storage conditions. For 8 weeks, they applied the base as well as the formulation to the cheeks of human volunteers, with weekly evaluations indicating that the formulation as opposed to the base yielded significant improvement, irrespective of time elapsed, in skin moisture content and erythema. The authors concluded that their T. chebula topical cream was effective in rejuvenating human skin.13
Wound healing
In 2002, Suguna et al. investigated in vivo the effects of a topically administered alcohol extract of the leaves of T. chebula on the healing of rat dermal wounds. The researchers found that treatment with T. chebula accelerated wound healing, with improved contraction rates and shorter epithelialization periods. T. chebula treatment yielded a 40% increase in the tensile strength of tissues from treated wounds. The authors concluded that T. chebula is beneficial in speeding the wound healing process.2
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.
References
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Dr. Baumann is chief executive officer of the Baumann Cosmetic & Research Institute in the Design District in Miami. She founded the Cosmetic Dermatology Center at the University of Miami in 1997. Dr. Baumann wrote the textbook, “Cosmetic Dermatology: Principles and Practice” (New York: McGraw-Hill, 2002), and a book for consumers, “The Skin Type Solution” (New York: Bantam Dell, 2006). She has contributed to the Cosmeceutical Critique column in Dermatology News since January 2001. Her latest book, “Cosmeceuticals and Cosmetic Ingredients,” was published in November 2014. Dr. Baumann has received funding for clinical grants from Allergan, Aveeno, Avon Products, Evolus, Galderma, GlaxoSmithKline, Kythera Biopharmaceuticals, Mary Kay, Medicis Pharmaceuticals, Neutrogena, Philosophy, Topix Pharmaceuticals, and Unilever.
