An integrated approach for assessing antimicrobial constituents from Angelica keiskei Koidzumi

Natural products are an outstanding source of biologically active molecules. More than two-thirds of anti-infective drugs currently on the market originate from natural sources [1]. Despite their contribution to medicine, the complexity of natural products, particularly botanicals, leads to many analytical challenges. The goal of this project is to investigate the antimicrobial activity of botanical medicines by integrating classic approaches such as bioactivity-guided fraction with novel technologies including biochemometrics [2] and molecular networking [3]. Angelica keiskei Koidzumi (Apiaceae), or ashitaba, is a botanical supplement native to Japan rich in bioactive chalcones, flavanones, and coumarins [4]. Ethyl acetate soluble fractions of ashitaba aerial and root powders inhibited the growth of methicillin-resistant Staphylococcus aureus (MRSA) at 10 µg/mL. The aerial extract was fractionated using normal-phase and reverse-phase chromatography and evaluated for antimicrobial activity. Unique bioactivity data were combined with mass spectral profiles to generate a selectivity ratio that identified compounds associated with the antimicrobial activity of the fractions. Fragmentation data were utilized to produce molecular networks that clustered related compounds together utilizing the Global Natural Products Social Molecular Networking site [3]. Biochemometric analysis identified xanthoangelol and 4-hydroxyderricin, known antimicrobial chalcones [5], as putative antimicrobial compounds, along with ions that have not been characterized in ashitaba. Nineteen out of the top thirty contributors to bioactivity also appeared in the same molecular networks, indicating that uncharacterized antimicrobial chalcones may be present.

Acknowledgements: Recognition is given to Laura Sanchez for her support with molecular networking.

Keywords: antimicrobials, biochemometrics, molecular networking, ashitaba.

References:

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No conflict of interest has been declared by the author(s).