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Cryptocarya densiflora Blume (Lauraceae) is an evergreen tree widely distributed throughout the hills and mountain forests up to 1500 m in Malaysia and Indonesia. The plant has been reported to contain phenanthroindolizidine-type of alkaloids. In the present work, a new phenanthroindolizidine alkaloid named ( R)-13a α-densiindolizidine, was isolated from the dichloromethane (DCM) extract of the leaves. The structure of the alkaloid was established based on 1D and 2D nuclear magnetic resonance (NMR) and liquid chromatography mass spectrometry-ion trap-time of flight (LCMS-IT-TOF) analysis. ( R)-13a α-densiindolizidine displayed binding interactions with crucial amino acid residues in the active sites ofsevere acute respiratory syndrome coronavirus 2 Mpro (SARS-CoV-2 Mpro) and RNA-dependent protease (RdRp) in silico, whilst fulfilling theabsorption, distribution, metabolism, excretion, and toxicity (ADMET) criteria and Lipinsky's rule, thus revealing its potential as a lead compound.

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Phytochemical investigation of the dichloromethane crude extract from the bark of Ochreinauclea maingayi with the aid of LCMS/MS-based molecular networking guided the isolation and accelerated the elucidation of known and new indole alkaloids. The molecular networking analysis produces two main clusters, along with 41 non-prioritized clusters and self-loop nodes. Each cluster has several nodes which depict the fractions contained within those nodes. An implementation of a fraction mapping for each node represents the molecular weight and key fragment data of each compound. From the analysis of each cluster and node, we can deduce the indole alkaloids are the scaffold of interest. Indole scaffold can be found between F5 and F10 that contain several types of indole alkaloids. In total, we have successfully purified nine indole alkaloids, including 9H-β-carboline-4-carboxylate 2, norharmane 3, harmane 4, naucledine 10, neonaucline 15, 1,2,3,4-tetranorharmane-1-one 16, naulafine 19, cadambine 9, and a new monoterpene indole alkaloid dihyrodeglycocadambine 7 from F5 to F10 using a chromatographic technique. Their structures were confirmed by 1D-NMR, 2D-NMR, UV, IR, LCMS, and MS2LDA. Several clusters and nodes contain ions that could not be annotated, suggesting that they may possess novel compounds that are yet to be discovered.