Identification and Characterization of Phytochemicals from Peanut (Arachis hypogaea L.) Pods

Methanol extracts of peanut (Arachis hypogaea L.) pods were chromatographed, which yielded 3 phytochemicals 1-3 including 5,7-dihydroxychromone (1), eriodictyol (2), and 3',4',5,7-tetrahydroxyflavone (3). To confirm the presence of isolated phytochemicals, the pods extracts were performed by high performance liquid chromatography coupled with a photodiode array detector (HPLC-PDA) and a mass spectrometric detector (MSD) with electrospray ionization (ESI). Optimum extraction conditions for phytochemical contents using peanut germplasm were obtained by employing 90% MeOH for 12 hr at room temperature and phytochemicals 1-3 showed significant differences with concentrations of $407.56{\pm}23.35$, $52.92{\pm}5.11$, and $2,024.34{\pm}134.18\;{\mu}g/g$, respectively. Under this optimal conditions, the contents of phytochemicals 1-3 in peanut pods of 3 Korea cultivars including 'Jakwang', 'Daekwang', and 'Palkwang' exhibited phytochemical 3 was the highest range of $1,338.01-5,162.93\;{\mu}g/g$, followed by phytochemical 1 ($590.13-1,382.10\;{\mu}g/g$), and phytochemical 2 ($25.12-186.85\;{\mu}g/g$), respectively. Moreover, 'Jakwang' exhibited the highest contents of phytochemical (1: $1,362.10{\pm}52.49$, 2: $186.85{\pm}17.69$, and 3: $5,162.93{\pm}148.64\;{\mu}g/g$, respectively), whereas the lowest contents was found in the 'Daekwang' (1: $590.13{\pm}22.23$, 2: $25.12{\pm}2.45$, and 3: $1,338.01{\pm}62.17\;{\mu}g/g$, respectively). These results suggest that the methanol extracts of peanut pods may possess health related benefits to humans owing to various known biological activities of phytochemicals 1-3.