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microbial, anti-inflammatory and anti-cancer effects (Fig. 4). Some of the bioactive

compounds reported earlier to be present in the plant include spilanthol, β-caryophyllene,
stigmasterol, sitosterol, α-amyrin, β-amyrin etc [4]. The compounds were identified based on

molecular formula, molecular structure, retention time and peak area of the spectrum.
Interestingly, four bioactive compounds namely (1) 2-Methoxy-4-vinylphenol (C9H10O2) (2)

Neophytadiene (C20H38) (3) N-Isobutyl-10-(isobutylcarbonyloxy)(2E,6Z,8E)-decatrienamide
(C19H31NO3) and (4) α-tocopherol (C29H50O2) that have never been reported earlier to be

present in S. acmella were also identified in the present study (Fig. 5). Besides, a number of

organic acids such as stearic acid, palmitic acid, linoleic acid, pipecolinic acid and their
methyl esters were also observed to be present particularly in the flowers of the plant (Table

1). Many of these compounds are known to play active roles in various biological activities.

N-Isobutyl-10-(isobutylcarbonyloxy)(2E,6Z,8E)-decatrienamide, the alkamide derivative of
spilanthol or (2E,6Z,8E)-N-Isobutyl-2,6,8-decatrienamide was observed to be present in large

scale (14.05%) in the plant. The phytosterols, β-sitosterol and stigmasterol are known to
possess antioxidant, anti-inflammatory, antipyretic and antineoplastic activities [23]. The

alkamide spilanthol exhibited anti-inflammatory effect through inhibition of iNOS expression
via down-regulation of several transcription factors in LPS and IFNγ stimulated raw

macrophages [3]. Similarly α-amyrin, β-caryophyllene, vanillic acid, trans-ferulic acid and

scopoletin also inhibited nitric oxide production in the activated raw macrophages [3].
Further β‐caryophyllene has also been reported to help in the mineralization of bones thereby

inhibiting adipogenesis and osteoclastogenesis [24]. Among the fatty acids, stearic acid helps
in the regulation of serum cholesterol level by lowering low-density lipoprotein (LDL), while

myristic acid possesses anti-inflammatory and antimicrobial properties [25,26]. Moreover α-
linolenic acid is a naturally occurring plant-based essential omega-3 fatty acid usually

obtained from the diets. It reduces high-fat diet induced abnormal lipid metabolism and helps

in preventing atherosclerosis and heart attacks thereby regulating cholesterol level and blood
pressure in the body [27].

Evaluation of cytotoxic effects of different parts of S. acmella on three cancer cell

lines (a) MCF-7 (b) A549 and (c) Saos-2 using MTT assay illustrated significant inhibition of
cell viability at higher concentrations (50 and 100 μg/ml) (Fig. 6). The flower extract

exhibited comparatively higher cytotoxic effect against the cancer cell lines MCF-7, A549
and Saos-2 with IC50 values of 22.20, 18.39 and 25.98 μg/ml respectively. The inhibition of

viability of cancer cell lines by S. acmella extracts in the present study may be due to entity
or synergistic effects of anticancer compounds present. Some of the bioactive compounds

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