A phytochemical investigation of the stem bark of Calophyllum canum resulted in the isolation of a new xanthone dimer identified as biscaloxanthone (1), together with four compounds; trapezifoliaxanthone (2), trapezifolixanthone A (3), taraxerone (4) and taraxerol (5). The structures of these compounds were determined via spectroscopic methods of IR, UV, MS and NMR (1D and 2D). The cytotoxicity of compounds 1-3 were screened against A549, MCF-7, C33A and 3T3L1 cell lines, wherein weak cytotoxic activities were observed (IC50 > 50 μm).
Gynura procumbens (Lour.) Merr. (Family: Asteraceae) is a tropical Asian medicinal plant found in Thailand, China, Malaysia, Indonesia, and Vietnam. It has long been utilized to treat a variety of health concerns in numerous countries around the world, such as renal discomfort, constipation, diabetes mellitus, rheumatism, and hypertension. The chemical investigation resulted in the isolation and characterization of six compounds from the methanol (MeOH) extract of the leaves of Gynura procumbens, which were identified as phytol (1), lupeol (2), stigmasterol (3), friedelanol acetate (4), β-amyrin (5), and a mixture of stigmasterol and β-sitosterol (6). In-depth investigations of the high-resolution 1H NMR and 13C NMR spectroscopic data from the isolated compounds, along with comparisons to previously published data, were used to clarify their structures. Among these, the occurrence of Compounds 1 and 4 in this plant are reported for the first time. The crude methanolic extract (CME) and its different partitionates, i.e., petroleum ether (PESF), chloroform (CSF), ethyl acetate (EASF), and aqueous (AQSF) soluble fractions, were subjected to antioxidant, cytotoxic, thrombolytic, and anti-diabetic activities. In a DPPH free radical scavenging assay, EASF showed the maximum activity, with an IC50 value of 10.78 µg/mL. On the other hand, CSF displayed the highest cytotoxic effect with an LC50 value of 1.94 µg/mL compared to 0.464 µg/mL for vincristine sulphate. In a thrombolytic assay, the crude methanolic extract exhibited the highest activity (63.77%) compared to standard streptokinase (70.78%). During the assay for anti-diabetic activity, the PESF showed 70.37% of glucose-lowering activity, where standard glibenclamide showed 63.24% of glucose-reducing activity.