Isolation and Tentative Characterization of a Genistein-like Compound from the Mistletoe Dendrophthoe pentandra (L.) Miq.

Dendrophthoe pentandra (L.) Miq., a hemiparasitic mistletoe widely used in Indonesian traditional medicine, is abundant in flavonoids; nevertheless, many of these compounds are inadequately characterized beyond the well-known flavonols. This study aimed to isolate and characterize a putative genistein-like compound, metabolomics standard initiative level 2–3, from the ethyl acetate fraction of leaves using a multi-instrument analytical approach. Reverse phase high performance liquid chromatography analysis revealed prominent peaks with retention times comparable to those of a genistein reference in both analytical and preparative conditions. The Fourier transform infrared spectroscopy spectrum of the isolate exhibited functional groups characteristic of an isoflavone framework, including phenolic O–H stretching, conjugated C=O carbonyl bands, and aromatic C=C and C–O vibrations. High-resolution liquid chromatography–electrospray ionization–tandem mass spectrometry quadrupole time-of-flight analysis detected a deprotonated molecular ion M–H - at m/z 269.0449, along with diagnostic fragment ions consistent with retro-Diels–Alder cleavage commonly observed in isoflavone aglycones. Although the analysis remained semi-quantitative and lacked orthogonal confirmation (e.g., nuclear magnetic resonance and peak-purity assessment), the combined analytical evidence was consistent with a tentative genistein-like annotation. Semi-quantitative recalculation indicated an estimated concentration of 0.5267 µg/mL in the injected ethyl acetate fraction, corresponding to an approximate relative abundance of 2.63% within the analyzed fraction. Because this value was below the estimated limit of quantification, the result should be interpreted as a relatively low-abundance estimate rather than a validated absolute quantitative measurement. These findings provide preliminary evidence supporting the possible occurrence of a genistein-like compound within the Loranthaceae family, although definitive structural confirmation requires further investigation.