Chemotyping and Determination of Antimicrobial, Insecticidal, and Cytotoxic Properties of Wild-Grown Cannabis sativa from Nepal

Abstract

Cannabis sativa was collected from a wildgrowing population in Biratnagar, Nepal. The essential oil was obtained by hydrodistillation and analyzed by gas chromatography – mass spectrometry. A total of 107 constituents were identified in the oil accounting for 94.2% of the composition. This Nepalese chemotype is characterized by a predominance of sesquiterpenoids (68.1%) dominated by (E)-caryophyllene (20.4%), αhumulene (7.0%), and α-bisabolol (5.8%), but a paucity of monoterpene hydrocarbons (0.9%). In particular, neither myrcene nor terpinolene were detected. The oil in the Nepalese Cannabis plants did contain small amounts of cannabidiol (1.6%), cannabichromene (0.2%) and Δ-tetrahydrocannabinol (0.4%). The essential oil from Nepalese Cannabis sativa was screened for antimicrobial, cytotoxic, larvicidal, and insecticidal activity, and it appears as though C. sativa is relatively non-toxic. INTRODUCTION Cannabis sativa L. is one of the three species of genus Cannabis that includes C. sativa, C. indica, and C. ruderalis (Guy et al., 2004). C. sativa, commonly known as “hemp” or “marijuana” in English and “bhang” or “ganja” in Nepali language, is an annual herbaceous, dioceous plant (Kriese et al., 2004). The origin of wild Cannabis is not known with certainty, but the plant, which appears to have been cultivated in northern China since 4000 BC (Mabberley, 2008), is widely distributed and cultivated throughout the world (Nigam et al., 1965). Some confusion and controversy regarding the taxonomy of Cannabis does exist. Small and Cronquist (1976) had proposed a monotypic genus, C. sativa with two subspecies, sativa and indica, while several others have recognized three different species, C. sativa, C. indica, and C. ruderalis (Schultes et al., 1974; Anderson, 1974, 1980; Emboden, 1974). Recent, genetic, morphological, and biochemical investigations have helped to delineate the three species of Cannabis (Hillig and Mahlberg, 2004; Hillig, 2004, 2005). C. sativa generally has lower levels of Δ-tetrahydrocannabinol (THC) than cannabidiol (CBD), while C. indica has less CBD than THC (Hillig and Mahlgerg, 2004). Wide-leaf varieties of C. indica have shown relatively high ratio of guaiol, γ-eudesmol, and βeudesmol, while the narrow-leaf varieties of C. indica have a relatively high ratio of (E)-β-farnesene (Hillig, 2004). The essential oil of Cannabis has demonstrated antimicrobial activity (Novak et al., 2001; Nissen et al., 2010) and mosquito larvicidal activities (Pavela, 2009). In the current study, the composition, chemotype, and bioactivities of the essential oil from a wild-growing Cannabis plant, tentatively identified as C. sativa, from Biratnagar, Nepal, were investigated. MATERIALS AND METHODS Plant material. Flowering Cannabis plants collected from city of Biratnagar (26°28′ N, 87°16′ E, Satyal and Setzer: Chemotyping and Determination of Antimicrobial, Insecticidal, and