Phytochemicals from Calophyllum canum Hook f. ex T. Anderson and their neuroprotective effects

Abstract

Previous phytochemical investigations reported that Calophyllum spp have biosynthesized a wide range of bioactive phenolics such as xanthones and coumarins. The phytochemical study conducted on the stem bark of C. canum has led to the isolation of eight trioxygenated xanthones namely: 5-methoxytrapezifolixanthone (1), 5-methoxyananixanthone (2), caloxanthone C (3), 1,5-dihydroxy-3-methoxy-4-isoprenylxanthone (4), 6-deoxyisojacareubin (5), euxanthone (6), trapezifolixanthone (7), ananixanthone (8), together with three common triterpenoids, β-sitosterol (9), friedelin (10), and stigmasterol (11). Furthermore, xanthones 1 and 2 were isolated for the first time as naturally occurring xanthones from the plant extract. The structures of these compounds were identified and elucidated using advanced spectroscopic techniques such as 1 D & 2 D NMR, MS, and FTIR. The neuroprotective property of selected compounds was tested through in vitro stroke model. Among all tested compounds, 1 µm of compounds 8, 9, and 10 showed significant neuroprotective activity via reduction of apoptosis by ∼ 50%.

Graphical Abstract

Keywords:

• Calophyllum canum
• xanthones
• triterpenoids
• neuroprotective
• stroke model

Acknowledgments

The authors would like to acknowledge the Sarawak Research Development Council (SRDC) (RDCRG/CAT/2019/11) and Universiti Teknologi MARA for financial assistance and support given throughout the research conducted on genus Calophyllum by MAL and VJYM. The Sarawak Biodiversity Centre (SBC) is also acknowledged.

Author contributions

MAL has contributed to writing-original draft preparation resources, VJYM conceptualization writing-review, supervision, and funding acquisition, WKL conceptualization writing-review and supervision, PC data acquisition review and editing, TK conceptualization writing-review and supervision.

Disclosure statement

The authors declare no conflict of interest.

Funding

The research project conducted by VJYM, MAL, WKL, TK was funded by Sarawak Research Development Council (SRDC) (RDCRG/CAT/2019/11)..