Radical scavenging activity and cytotoxicity of active quinic acid derivatives from Scorzonera divaricata roots.

Five new quinic acid derivatives and two known 3-O-feruloylquinic acids were isolated from the roots of Scorzonera divaricata Turcz. The new compounds were elucidated as (-)-1,4-di-O-feruloyl-3-O-dihydrocaffeoylquinic acid, (-)-1-O-feruloyl-4-O- dihydrocaffeoylquinic acid, (-)-3,5-di-O-feruloylquinic acid, (-)-1-O-feruloyl-3-O-dihydro- caffeoylquinic acid, and (-)-1-O-feruloyl-5-O-dihydrocaffeoylquinic acid based on extensive spectroscopic studies, including one- and two-dimensional NMR, HRESIMS, UV, and IR results. Five compounds were assessed for antioxidant activity by ABTS and DPPH radical-scavenging assays and for their cytotoxicity against HL-60 and Hep-G2 cell lines by the MTT assay. Three quinic acid derivatives exhibited strong antioxidant activity, with IC(50) values of 3.95, 5.87, and 7.45 µg/mL against ABTS(+) and 11.7, 13.6, and 50.1 µg/mL against DPPH(). (-)-1,4-Di-O-feruloyl-3-O-dihydrocaffeoylquinic acid also exhibited moderate activity against Hep-G2 cell lines with an IC(50) value of 14.6 µg/mL.

Triterpenes and neolignans from the roots of Nannoglottis carpesioides.

Seven oleanane-type triterpenes and two 8-O-4'-neolignans, along with five known compounds (three 28-noroleanane-type triterpenes, one sarratane triterpene, and one neolignan), were isolated from roots of Nannoglottis carpesioides. Their structures were elucidated by spectroscopic methods, including 1D and 2D NMR, HRMS, and CD. The absolute configurations of two triterpenes were determined by experimental and calculated circular dichroism (CD) and optical rotation values. Ten compounds were evaluated for their cytotoxicity against human promyelocytic leukaemia (HL-60) and human hepatoma (Hep-G2) cells using the MTT assay. The antioxidant activities of these compounds were assessed by ABTS radical-scavenging assays. Among the tested compounds, three compounds exhibited moderate radical-scavenging activity against ABTS·âº, with IC50 values of 22.4, 17.4, and 23.2 µM, respectively.

Nitric oxide enhances aluminum tolerance by affecting cell wall polysaccharides in rice roots.

Nitric oxide (NO) is a key signal molecule involved in many physiological processes in plants. To study the mechanisms of exogenous NO contribution to alleviate the aluminum (Al) toxicity, roots of rice (Oryza sativa) seedlings pre-treated with sodium nitroprusside (SNP, a NO donor) were used to investigate the effect of Al in this study. Results indicated that NO alleviated the lipid peroxidation induced by Al and promoted the root elongation, whereas butylated hydroxyanisole (BHA), an efficient lipophilic antioxidant, alleviated the lipid peroxidation only. Rice seedling roots pre-treated with SNP followed by Al treatment had lower contents of pectin and hemicellulose, lower Al accumulation in root tips and cell walls, higher degree of methylation of pectin and lower wall Al-binding capacity than the roots with Al treatment only. Therefore, the decreased Al accumulation in the cell walls of rice roots is likely to be the reason for the NO-induced increase of Al tolerance in rice, and it seems that exogenous NO enhanced Al tolerance in rice roots by decreasing the contents of pectin and hemicellulose, increasing the degree of methylation of pectin, and decreasing Al accumulation in root cell walls.