Abstract
BACKGROUND: In the Southern Tibet region, the Nepalese and Indian Himalayas many plants rich in aromatic resins are burned by populations who follow Tantric Buddhism, for both daily sacred activities and religious ceremonies. The main plant material used are branches of Juniperus indica Bertol. (Cupressaceae) and Rhododendron anthopogon D.Don (Ericaceae). The harvesting of these species, considered as sacred, is an ancient custom linked to folk medicine and the production of incense for religious practices or to purify the domestic environment as their essential oils (EOs) promote tranquility. We present here a study which, starting from a survey of the ethnobotanical uses of these two species, describes the traditional methods of collection and distillation in Nepal. Furthermore, we show the phytochemical profile of the two EOs and their biological activity on Central Nervous System (CNS), specifically their effectiveness in anti-acetylcholinesterase and anti-butyrylcholinesterase tests. METHODS: We recorded the methods of collection and distillation as recounted in an open interview (with an informed consent) with the local lama, whose family, for centuries, has been responsible for a household gompa and the rituals associated with it. The locally distilled EOs from the two species were phytochemically characterized by GC and GC-MS. Essential oils and their main constituents were then tested for their possible in vitro effects on the Central Nervous System, by assessing their activity on anti-acetylcholinesterase and anti-butyrylcholinesterase activities. RESULTS: The phytochemical profiles showed α-terpinene (38.21%) and α-pinene (10.73%) as main constituents in J. indica, and α-pinene (23.10%) and β-pinene (11.42%) in R. anthopogon. The anti-acetylcholinesterase and anti-butyrylcholinesterase assays showed that both EOs have a moderate inhibitory activity against acetylcholinesterase and butyrylcholinesterase. CONCLUSIONS: Ethnobotanical data collected confirm the high ritual value of J. indica and R. anthopogon in the Indian Himalaya for both Tantric religious ceremonies and in the daily activity. The data obtained on the chemical composition of the EOs distilled on-site from these species and on their inhibitory activity on important enzymes of the CNS can validate, at least in part, the traditional use linked to their anxiolytic properties. The possible application of these EOs in the aromatherapy market, respecting traditional and eco-sustainable methods of collection and distillation, can represent a further source of income for local populations.