Vernonia species (Asteraceae) are indigenous medicinal and food leaf vegetables commonly consumed in some African countries like Cameroon where they constitute a staple dish called “ndolé.” Previous studies have demonstrated the nutritional importance of Vernonia, but there is little knowledge of their agronomic value and genetic potentials. Wide genetic variability in the genus has been established earlier through the study of its pollen. However, to the best of our understanding, no such study has been undertaken on the genetic variability of Vernonia with respect to its secondary metabolites. This study was therefore aimed at evaluating the genetic variability of Vernonia amygdalina (VAA and VALF) and V. calvoana (VCAB, VCAV, VCSB, and VCSV) morphotypes in 2016 based on secondary metabolite content and antimicrobial properties. This involved phytochemical analysis by HPLC/MS for the detection of alkaloids, flavonoids, phenols, and tannins in leaves from each of the six genotypes. Results showed that all tested genotypes are rich in phenols (18 analyzed), flavonoids, and tannins with, VAA richer in phenols (206.1 ± 3.12 µg/g of dry extract), followed by VCAV (197.9 ± 18.03 µg/g). The lowest level of flavonoid was found in VCSV (81.6 ± 7.21 µg/g), while the highest was from VCAB (132.8 ± 31.5 µg/g). VCSV (56.3 ± 4.08 µg/g) had the lowest level of tannins, while VCAB (97.8 ± 23.8 µg/g) had the highest levels. Assessment of antimicrobial activity of leaf extracts from the six genotypes was done by culture on Mueller Hinton (MH) agar and MH broth agar for bacteria and in Sabouraud dextrose agar and Sabouraud dextrose broth media for fungi, respectively. All morphotypes exhibited inhibitory activity on bacteria except VAA, with isoquercetin characteristic of VCSV. Chemotaxonomic analyses of Vernonia morphotypes highlighted the genetic diversity within species and variability of antimicrobial properties of ethanolic leaf extracts among morphotypes. These results provide baseline data in the valuation of genetic resources and the establishment of improvement programs.

中文翻译：

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叶提取物的次生代谢物含量和抗菌活性揭示了杏仁斑鸠菊和斑斑斑鸠菊形态型的遗传变异

斑鸠菊科（菊科）是当地的药用和食用叶菜，在喀麦隆等一些非洲国家常见，它们构成了一种名为“ndolé”的主食。先前的研究已经证明斑鸠菊的营养重要性，但对其农艺价值和遗传潜力知之甚少。通过对其花粉的研究，早先已经确定了该属的广泛遗传变异性。然而，据我们所知，尚未对斑鸠菊属的次生代谢物的遗传变异性进行此类研究。因此，本研究旨在评估杏仁斑鸠菊（VAA 和 VALF）和V的遗传变异性。卡尔沃阿纳（VCAB、VCAV、VCSB 和 VCSV）2016 年基于次级代谢物含量和抗菌特性的形态型。这涉及通过 HPLC/MS 进行植物化学分析，以检测来自六种基因型中每一种的叶子中的生物碱、黄酮类化合物、酚类和单宁。结 VCSV 中黄酮类化合物含量最低 (81.6 ± 7.21 µg/g)，而 VCAB 含量最高 (132.8 ± 31.5 µg/g)。VCSV (56.3 ± 4.08 µg/g) 的单宁含量最低，而 VCAB (97.8 ± 23.8 µg/g) 的单宁含量最高。通过分别在 Mueller Hinton (MH) 琼脂和 MH 肉汤琼脂培养基上培养细菌以及在 Sabouraud 葡萄糖琼脂和 Sabouraud 葡萄糖肉汤培养基上培养真菌，对来自六种基因型的叶提取物的抗菌活性进行评估。除VAA外，所有形态型均表现出对细菌的抑制活性，具有VCSV的异槲皮素特征。化学分类学分析斑鸠菊形态型突出了物种内的遗传多样性和形态型之间乙醇叶提取物的抗菌特性的变异性。这些结果为遗传资源估价和改进计划的制定提供了基线数据。