Abstract
Zanthoxylum paracanthum Kokwaro (Rutaceae) is an endemic Kenyan and Tanzanian plant used in folk medicine by local populations. Although other Zanthoxylum species have been studied, only Z. paracantum stem extracts have been profiled, even though the roots are also used as herbal remedies. As root extracts may be another source of pharmaceutical compounds, the CH2Cl2/MeOH (1:1) root bark extract was studied in this report. Eight root bark compounds were isolated and their structural identities were confirmed by mass spectrometry (MS) and nuclear magnetic resonance (NMR) (using COSY, HSQC, NOESY and HMBC) analyses. The structural identities were determined as follows: the fatty acid—myristic acid (1); the sterol—stigmasterol (2); the lignan—sesamin (3); two β-carboline alkaloids—10-methoxycanthin-6-one (6) and canthin-6-one (7); and three phenanthridine alkaloids—8-acetonyldihydrochelerythrine (4), arnottianamide (5) and 8-oxochelerythrine (8). Some of these compounds were identified in the species for the first time. These compounds and the extract were then tested in vitro against methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 29213) and Candida albicans (ATCC 10231) before tests for antiproliferative activity against the human breast cancer (HCC 1395), human prostate cancer (DU 145) and normal (Vero E6) cell lines were conducted. Minimum inhibition concentration values of 3.91, 1.95, 0.98 and 7.81 µg/mL against MRSA, S. aureus, E. coli and C. albicans, respectively, were recorded. Among the isolates, canthin-6-one was the most active, followed by 10-methoxycanthin-6-one. The root extract and some of the compounds also had antiproliferative activity against the HCC 1395 cell line. Stigmasterol and canthin-6-one had IC50 values of 7.2 and 0.42. The root bark extract also showed activity, at 8.12 µg/mL, against the HCC 1395 cells. Out of the chemical isolates, 10-methoxycanthin-6-one and canthin-6-one showed the strongest inhibition of the DU 145 cells. The root extract had significant antimicrobial and antiproliferative activities, supporting the traditional use of this plant in treating microbial infections and cancer-related ailments.
Highlights
Medicinal plants remain an important source of pharmaceutics, and in communities where access to healthcare is limited, plant-based medications have a high proportion of use [1]
There is a global commitment to finding new drug entities that are effective in reducing the proliferation of cancers [5]
As the root bark extract of Z. paracanthum has never been studied in this way before, we identified this extract as a possible new source of bioactive compounds
Summary
Medicinal plants remain an important source of pharmaceutics, and in communities where access to healthcare is limited, plant-based medications have a high proportion of use [1]. The use of herbal medicines to treat different ailments, including infectious diseases and cancers, is common [2]. In Kenya, breast, cervical, oesophageal, colon, stomach and ovarian cancers occur at higher incidents in women, while in men, prostate, oesophageal, colon, stomach, oral and liver cancers are most prevalent [3]. Higher levels of cancers are becoming more apparent, and a recent study in 2019 showed that there are more female cancer cases than male; 60% and 56.4%, respectively [4]. There is a global commitment to finding new drug entities that are effective in reducing the proliferation of cancers [5]. In the search for new plant-derived pharmaceuticals, the candidate drug should demonstrate selectivity by having low levels of toxicity to normal cell lines, and superior cytotoxicity towards cancer cell lines [6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
