Isolation, X-ray crystal structure and DFT calculations for 9β,13β-epoxy-7-abietene from the essential oil of Tetradenia riparia

Abstract

Resveratrol (RES, 3,5,4′-trihydroxy-E-stilbene) is a highly researched natural polyphenolic nutraceutical due to its extensive range of health benefits, including antibacterial, antioxidant, anti-inflammatory, and anticarcinogenic properties. However, this polyphenolic compound presents low solubility in water. Here, its cocrystal with calix[4]tube was synthesized using the solution cocrystallization technique. It was subsequently elucidated by single crystal X-ray diffraction technique, infrared spectroscopy, thermogravimetry (TG) and differential scanning calorimetry (DSC). The solubility of the cocrystal was tested together with that of the pure nutraceutical compound. The results demonstrated that the RES solubility in the cocrystal was around twice that of the pure nutraceutical solid state form. Therefore, the solubility of RES is significantly enhanced by the pharmaceutical cocrystal, presenting a potential strategy for improving poorly soluble active pharmaceutical and food ingredients.