Variation of Phytochemicals in Leaves of Seven Accessions of Hibiscus sabdariffa Grown under Field, Green Roof, and High Tunnel Conditions

The phytochemical composition in the leaves of seven accessions of Hibiscus sabdariffa L. grown under field, green roof, and high tunnel conditions was investigated in the present study. Principle component analysis of freeze-dried leaves using near-infrared (NIR) spectral fingerprinting revealed differences between accessions and the three growing conditions. Under all conditions, NIR fingerprint data of accession PI 286316 showed variation from the other six accessions (PI 256041, PI 267778, PI 273388, PI 275414, Thai red, and UDC green). A detailed investigation of the phytochemical composition of the accessions by highperformance liquid chromatography coupled with diode array and high-resolution mass spectrometry showed the presence of 16 bioactive phenolics. In six accessions, ten phenolics were identified as compared to eight phenolics in accession 286316, six of which from the latter were unique and not previously reported in H. sabdariffa leaves. Only two phenolics, namely neochlorogenic acid and chlorogenic acid, were common in all seven accessions. Total phenolics in samples from the green roof were 12% and 16% higher than those from the field and high tunnel, respectively. Ten free soluble amino acids and three soluble sugars were identified in all accessions. However, total amino acids and sugars in leaves from the field were between 24 and 42% higher than leaves from the green roof and high tunnel. This study shows that H. sabdariffa leaves provide a good source for bioactive phenolics, free amino acids, and sugars, hence, it can be a nutritious addition to meals.