Abstract
BackgroundA large number of secondary metabolites can be obtained from plants used for traditional medicine in two related genera (Ixora and Greenea) in the subfamily Ixoroideae (Rubiaceae), but there are only a few detailed studies on their bioactivities. Therefore, the main goals of this study were to determine the antibacterial activities of lipophilic extracts from plants of some Ixora and Greenea species native to Thailand, and to isolate some pure compounds from those extracts. Moreover, we compared the occurrence of compounds in different plant parts of samples from different habitats to better understand their variation.MethodsA total of 56 lipophilic extracts were obtained from the leaves, stem bark, and root bark of eight Ixora and two Greenea species collected at various locations in Thailand. Isolated compounds were identified using nuclear magnetic resonance. Antimicrobial activities were evaluated against four Gram-positive and nine Gram-negative human pathogenic bacterial strains.ResultsExtracts from I. javanica, I. nigricans, I. brunonis, and G. montana, along with isolated scopoletin, exhibited antibacterial activities against Gram-positive methicillin-resistant Staphylococcus aureus ATCC 43300, with minimum inhibitory concentration values ranging from 64 to 256 µg/mL. The occurrence of scopoletin, isofraxidin, and geniposidic acid in lipophilic extracts showed some variation among different plant parts and species.ConclusionsLipophilic extracts of Ixora and Greenea species have the potential to be developed as anti-Gram-positive agents, in particular to counter infections of methicillin-resistant S. aureus strains. The chemical profiles showed differences between floristic regions but similarity within the same plant parts.
Highlights
As the resistance of microorganisms to available antibiotics increases, plant sources have become an attractive alternative for new drug discovery (Cowan, 1999)
The genus Greenea was only represented by two species (G. corymbosa and G. montana) because the other species reported from Thailand are only available as herbarium specimens or are limited to areas not accessible for collecting (Tange, 2013)
Occurrence pattern of coumarins and iridoid in the studied Ixora and Greenea species Phytochemical examination and isolation of extracts from Ixora and Greenea species revealed three known compounds: two coumarins, scopoletin (1) and isofraxidin (2), and one iridoid glycoside, geniposidic acid (3). These compounds were identified using nuclear magnetic resonance (NMR) spectroscopy. The occurrences of these compounds varied among extracts from different plant parts in species of both genera collected from different provinces (Table 1)
Summary
As the resistance of microorganisms to available antibiotics increases, plant sources have become an attractive alternative for new drug discovery (Cowan, 1999). Species such as I. brunonis, I. cibdela, I. javanica, and I. nigricans are used to treat fevers, ophthalmic diseases, ear infections, wounds infections, dysentery, and diarrhea (Table S1) These diseases are mostly caused by bacteria and viruses; Ixora species are potential natural sources for antimicrobial drug development. Results: Extracts from I. javanica, I. nigricans, I. brunonis, and G. montana, along with isolated scopoletin, exhibited antibacterial activities against Gram-positive methicillin-resistant Staphylococcus aureus ATCC 43300, with minimum inhibitory concentration values ranging from 64 to 256 mg/mL. Conclusions: Lipophilic extracts of Ixora and Greenea species have the potential to be developed as anti-Gram-positive agents, in particular to counter infections of methicillin-resistant S. aureus strains. The chemical profiles showed differences between floristic regions but similarity within the same plant parts
Sign-in/Register to view highlights & summary 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.
