The fruits of Mallotus philippinensis are an underexplored source of chemically diverse and biologically active natural products, previously reported to exhibit anti-inflammatory, antiviral, and cytotoxic activities. In this study, ion identity molecular networking (IIMN) resulted in the discovery of four previously undescribed phenolic derivatives (runakamalas A-D (1-4)), together with the known compounds mallotophilippen F (5), 3',4'-dihydroxyrottlerin (6), and 4'-hydroxyrottlerin (7). Their structures were elucidated by HRESIQTOF-MS, MS/MS fragmentation analysis, and NMR spectroscopy. The absolute configurations of 1 and 2 were clarified by vibrational circular dichroism (VCD) spectroscopy supported by quantum-chemical calculations, while the enantiomers of racemic 3 were separated by chiral-phase HPLC, and their absolute configurations were determined by a comparison of experimental and TDDFT-calculated ECD spectra. Among the new isolates, 4 is distinguished by a linear C-8-C-1'-C-4' chain, an unusual structural feature compared with other phloroglucinol derivatives reported from this species. In addition, the structure of compound 5 was confirmed. All isolated compounds were evaluated for their cytotoxicity against the human neuroblastoma SH-SY5Y cell line and for their antioxidant activity using the DPPH radical scavenging assay.
Kieu et al. (2026) studied this question.