Contributions of Chemical Content and Biological Activity to Plant Taxonomy Based on the FourAlliumL. Taxa (Sect.Cupanioscordum‐ Amaryllidaceae)

Abstract

Garlic and onions are used as food and for medicinal purposes worldwide. Allium L. species are rich in bioactive organosulphur compounds that exhibit many biological activities like anticancer, antimicrobial, antihypertensive, antidiabetic activities. In this study, macro‐ and micromorphological characteristics of four Allium taxa were examined and the results suggested that A. callimischon subsp. haemostictum was the outgroup to sect. Cupanioscordum. Also, for the genus Allium, which is a taxonomically difficult genus, the hypothesis that chemical content and bioactivity can also be used taxonomically in addition to micro and macromorphological characters has been questioned. The bulb extract was analyzed to determine their volatile compositions and anticancer activities against human breast cancer, human cervical cancer, and rat glioma cells for the first time in the literature. To detect the volatiles, the Head Space‐Solid Phase Micro Extraction method was used followed by Gas Chromatography‐Mass Spectrometry. The main compounds were found as dimethyl disulfide that (36.9 %, 63.8 %, 81.9 %, 12.2 %) and methyl (methylthio)‐methyl disulfide (10.8 %, 6.9 %, 14.9 %, 60.0 %) for A. peroninianum, A. hirtovaginatum and A. callidyction, respectively. Additionally, methyl‐trans‐propenyl disulfide is detected for A. peroniniaum (36 %). As a result, all extracts have shown significant efficacy against MCF‐7 cells depending on applied concentrations. The treatment of MCF‐7 cells for 24 h with 10, 50, 200, or 400 μg/mL ethanolic bulb extract of four Allium species resulted in DNA synthesis inhibition. Survival rates for A. peroninianum was 51.3 %, 49.7 %, 42.2 %, 42.0 %, for A. callimischon subsp. haemostictum 62.5 %, 63.0 %, 23.2 %, 22 %, for A. hirtovaginatum 52.9 %, 42.2 %, 42.4 %, 39.9 %, for A. callidyction 51.8 %, 43.2 %, 39.1 %, 31.3 %, for cisplatin 59.6 %, 59.9 %, 50,9 %, 48.2 %, respectively. Moreover, taxonomic evaluation according to biochemical compounds and bioactivities is almost in agreement with that made according to micro and macromorphological characters.