Glycyrrhiza glabra is an important herb throughout the World. Glycyrrhizin is the major constituent of the rhizomes of Glycyrrhiza glabra. Fars and Khorasan provinces are the production poles of licorice in Iran. The present study (with a randomized factorial design) was performed in tree replications to determine the variation in phytochemical composition and antioxidant capacity on the licorice rhizomes (less than 1 and 1–2 cm diameters) of Fars (FA) and Khorasan (KH) populations in 2016 and 2017. Glycyrrhizin, saponin, phenolic compounds, and the flavonoid content, as well as antioxidant capacity of the rhizomes, were evaluated. Moreover, the metabolite profile of these two licorice populations was detected by GC–MS analysis. The results showed that these factors were significantly influenced by environmental factors and rhizome diameter. The highest glycyrrhizin (43 mg/g) and saponin (47 g/100 g DW) contents belonged to the thicker rhizomes of Fars population. Flavonoid showed a significant negative correlation with saponin and glycyrrhizin (r² = − 0.92 and 1− 0.87, respectively) while exhibiting a significant positive relationship with antioxidant activities (r² = 0.77). The high antioxidant capacity (by DPPH) or IC₅₀ values (the concentration showing 50% antioxidant activity) (0.66 mg/ml) were observed in the thinner rhizomes of the Khorasan population. Moreover, the constituents were isolated from the hydroalcoholic extract of the rhizomes of two licorice populations whose GC–MS results were different. The most abundant phytochemical compound was dihydro-p-coumaric acid in both populations. The results of PCoA, PCA-biplot, and cluster analysis revealed a low diversity between all the individuals of FA and KH populations. Phenolic compounds and flavonoid of the two populations had the largest amount of difference of traits. Thus, the different environmental conditions can dramatically influence the production of secondary metabolites and antioxidant capacity of G. glabra.

甘草是全世界重要的草药。甘草甜素是甘草根茎的主要成分。法尔斯和霍拉桑省是伊朗甘草的生产极地。本研究（采用随机因子设计）是在树木复制中进行的，以确定法斯（FA）和霍拉桑（KH）的甘草根茎（直径小于1和1-2厘米）的植物化学成分和抗氧化能力的变化。评估了2016年和2017年的总黄酮含量。对甘草酸，皂苷，酚类化合物，类黄酮含量以及根茎的抗氧化能力进行了评估。此外，这两个甘草种群的代谢产物通过GC-MS分析得到了检测。结果表明，这些因素受到环境因素和根茎直径的显着影响。最高的甘草甜素（43 mg / g）和皂苷（47 g / 100 g DW）含量属于Fars人群的较厚根茎。r ² 分别为-0.92和1-0.87），并且与抗氧化剂活性呈显着正相关（r ²  = 0.77）。高抗氧化能力（通过DPPH）或IC ₅₀在霍拉桑族群的较细根茎中观察到了0.65 mg / ml的值（​​显示出50％抗氧化活性的浓度）（0.66 mg / ml）。此外，从GC-MS结果不同的两个甘草种群的根茎水醇提取物中分离出成分。在这两个种群中，最丰富的植物化学化合物是二氢对香豆酸。PCoA，PCA-biplot和聚类分析的结果表明，FA和KH人群的所有个体之间的多样性较低。两个种群的酚类化合物和类黄酮具有最大的性状差异。因此，不同的环境条件可以极大地影响次生代谢产物的生产和G. glabra的抗氧化能力。