Analysis of bioactive components in Ghost chili (<i>Capsicum chinense</i>) for antioxidant, genotoxic, and apoptotic effects in mice

<p>Apart from using traditionally in culinary preparations, chili peppers are also important constituents of herbal medicines. Although the bioactive components are studied mostly in the fruits of <i>Capsicum annuum</i>, no such study reports till date is available for Ghost chili (<i>C. chinense</i>) from North East India. Therefore, the aim of this study was to carry out an analysis of the bioactive constituents in the naturally occurring hottest chili Ghost chili (<i>C. chinense</i>), and evaluate its antioxidant, pro/anti-genotoxic, and apoptotic effects in <i>in vitro</i> and <i>in vivo</i> models. Three different antioxidant assays showed that lower doses of Ghost chili extract showed higher DNA protective and antioxidant activities. Furthermore, the administration for 7 alternate days into 6 week old Swiss albino mice showed that the lower doses (50 and 100 mg/kg bw) reduced DMBA induced genotoxicity beside significantly enhancing the activities of hepatic antioxidant enzymes, while higher dose (200 mg/kg bw) induced genotoxic effect in bone marrow cells. The administration of higher dose (200 mg/kg bw) also induced apoptosis and upregulation of <i>Bax</i> (pro) and downregulation of <i>Bcl-2</i> (anti) apoptotic genes. Dose dependent increase of apoptosis was also observed in Hep G2 and Hep 3B liver cancer cell lines. Our findings in the present study suggest that low doses of <i>C. chinense</i> can exert cancer chemopreventive effects. The induction of apoptosis in both cancer cell lines and mouse bone marrow cells, and up-regulation of proapoptotic genes suggests that the higher dose of <i>C. chinense</i> can be used for targeted cancer therapy.</p

Comparative Analysis of Fruit Metabolites and Pungency Candidate Genes Expression between Bhut Jolokia and Other <i>Capsicum</i> Species

<div><p>Bhut jolokia, commonly known as Ghost chili, a native <i>Capsicum</i> species found in North East India was recorded as the naturally occurring hottest chili in the world by the Guinness Book of World Records in 2006. Although few studies have reported variation in pungency content of this particular species, no study till date has reported detailed expression analysis of candidate genes involved in capsaicinoids (pungency) biosynthesis pathway and other fruit metabolites. Therefore, the present study was designed to evaluate the diversity of fruit morphology, fruiting habit, capsaicinoids and other metabolite contents in 136 different genotypes mainly collected from North East India. Significant intra and inter-specific variations for fruit morphological traits, fruiting habits and 65 fruit metabolites were observed in the collected <i>Capsicum</i> germplasm belonging to three <i>Capsicum</i> species i.e., <i>Capsicum chinense</i> (Bhut jolokia, 63 accessions), <i>C</i>. <i>frutescens</i> (17 accessions) and <i>C</i>. <i>annuum</i> (56 accessions). The pungency level, measured in Scoville Heat Unit (SHU) and antioxidant activity measured by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay showed maximum levels in <i>C</i>. <i>chinense</i> accessions followed by <i>C</i>. <i>frutescens</i> accessions, while <i>C</i>. <i>annuum</i> accessions showed the lowest value for both the traits. The number of different fruit metabolites detected did not vary significantly among the different species but the metabolite such as benzoic acid hydroxyl esters identified in large percentage in majority of <i>C</i>. <i>annuum</i> genotypes was totally absent in the <i>C</i>. <i>chinense</i> genotypes and sparingly present in few genotypes of <i>C</i>. <i>frutescens</i>. Significant correlations were observed between fruit metabolites capsaicin, dihydrocapsaicin, hexadecanoic acid, cyclopentane, α-tocopherol and antioxidant activity. Furthermore, comparative expression analysis (through qRT-PCR) of candidate genes involved in capsaicinoid biosynthesis pathway revealed many fold higher expression of majority of the genes in <i>C</i>. <i>chinense</i> compared to <i>C</i>. <i>frutescens</i> and <i>C</i>. <i>annuum</i> suggesting that the possible reason for extremely high pungency might be due to the higher level of candidate gene(s) expression although nucleotide variation in pungency related genes may also be involved in imparting variations in level of pungency.</p></div

Range of antioxidant activity of different <i>Capsicum</i> species.

<p>Anti-oxidant activity using DPPH assay obtained for <i>C</i>. <i>chinense</i>, <i>C</i>. <i>frutescens</i> and <i>C</i>. <i>annuum</i> varieties and represented in 25mg/ml dilutions.</p

Morphological characteristics of <i>Capsicum</i> fruits.

<p>Morphological characteristics of <i>Capsicum</i> fruits.</p

Morphological diversity of <i>Capsicum</i> species.

<p>Selected <i>Capsicum</i> germplasm from North East India showing contrasting phenotypes for fruit morphology, color, and fruiting habits. Accessions in 1-3^rd rows are contrasting Bhut jolokia genotypes (<i>C</i>. <i>chinense</i>), 4^th and 5^th row contains <i>C</i>. <i>chinense</i>, <i>C</i>. <i>frutescens</i> and <i>C</i>. <i>annuum</i> accessions.</p

Principal component analysis of metabolites identified using gas chromatography–mass spectrometry (GC–MS) analysis.

<p>For GC–MS, different genotypes of <i>C</i>. <i>chinense</i> [Acc 1–63 (major accession formed red circle)], <i>C</i>. <i>frutescens</i> [Acc 64–80 (major accession formed blue circle)] and <i>C</i>. <i>annuum</i> [Acc 81–136 (major accession formed brown circle)] were analysed and the correlation variances explained by the PC1 and PC2 components are 51% and 11%, respectively.</p