Antiglycation and Antioxidant Activity from Methanol Extract and Fraction of Xylocarpus granatum Stem

The objective of this research was to determine the antioxidant and antiglycation activity of methanol crude extract of Xylocarpus granatum stem and its fraction. The methanol crude extract was fractioned by liquid-liquid extraction to obtain three fractions, which were n-hexane fraction, ethyl acetate fraction, and methanol fraction. Antioxidant activity was performed using scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH). The antiaging activity was identified based on the ability to inhibit the formation of advanced glycation end products (AGEs). The results of the study showed that methanol crude extract and all fractions had an antioxidant and antiglycation activity that significantly different from each other (P<0.05). The results show that the most active antiglycation and antioxidant activity was the methanol fraction with IC50 were 71.55 ppm and 8.52 ppm, respectively. The methanol fraction contained an alkaloid, flavonoid, phenolic, and triterpenoid compounds. Subsequent fractionation of the methanol fraction guided by bioassay showed that sub-fraction 1 had the best antiglycation and antioxidant activity. Based on the color of the chromatogram obtained at UV 366 nm, the chemical component contained in the most active fraction was the flavonoid group.

Twenty-Nine New Limonoids with Skeletal Diversity from the Mangrove Plant, Xylocarpus moluccensis

Twenty-nine new limonoids—named xylomolins A₁–A₇, B₁–B₂, C₁–C₂, D–F, G₁–G₅, H–I, J₁–J₂, K₁–K₂, L₁–L₂, and M–N, were isolated from the seeds of the mangrove plant, Xylocarpus moluccensis. Compounds 1–13 are mexicanolides with one double bond or two conjugated double bonds, while 14 belongs to a small group of mexicanolides with an oxygen bridge between C1 and C8. Compounds 15–19 are khayanolides containing a Δ^8,14 double bond, whereas 20 and 21 are rare khayanolides containing a Δ^14,15 double bond and Δ^8,9, Δ^14,15 conjugated double bonds, respectively. Compounds 22 and 23 are unusual limonoids possessing a (Z)-bicyclo[5.2.1]dec-3-en-8-one motif, while 24 and 25 are 30-ketophragmalins with Δ^8,9, Δ^14,15 conjugated double bonds. Compounds 26 and 27 are phragmalin 8,9,30-ortho esters, whereas 28 and 29 are azadirone and andirobin derivatives, respectively. The structures of these compounds, including absolute configurations of 15–19, 21–23, and 26, were established by HRESIMS, extensive 1D and 2D NMR investigations, and the comparison of experimental electronic circular dichroism (ECD) spectra. The absolute configuration of 1 was unequivocally established by single-crystal X-ray diffraction analysis, obtained with Cu Kα radiation. The diverse cyclization patterns of 1–29 reveal the strong flexibility of skeletal plasticity in the limonoid biosynthesis of X. moluccensis. Compound 23 exhibited weak antitumor activity against human triple-negative breast MD-MBA-231 cancer cells with an IC₅₀ value of 37.7 μM. Anti-HIV activities of 1, 3, 8, 10, 11, 14, 20, 23–25, and 27 were tested in vitro. However, no compounds showed potent inhibitory activity.