In vitro screening of five local medicinal plants for antibacterial activity using disc diffusion method

Area of Science:

• Pharmacognosy
• Microbiology
• Ethnobotany

Background:

• Medicinal plants are traditionally used for infectious diseases.
• Scientific validation is crucial for traditional medicinal plant claims.
• Malaysia possesses a rich diversity of medicinal flora with potential therapeutic applications.

Purpose of the Study:

• To evaluate the antibacterial activity of crude extracts from five Malaysian medicinal plants.
• To screen extracts against clinically relevant bacterial strains, including Methicillin-Resistant Staphylococcus aureus (MRSA).

Main Methods:

• Leaves of Andrographis paniculata, Vitex negundo, Morinda citrifolia, Piper sarmentosum, and Centella asiatica were extracted.
• Crude extracts were tested against Staphylococcus aureus, MRSA, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli.
• Disc Diffusion Method (DDM) was employed to assess antibacterial activity via inhibition zones and Minimum Inhibitory Concentration (MIC) values.

Main Results:

• Morinda citrifolia, Piper sarmentosum, and Centella asiatica methanol extracts exhibited activity against Gram-positive S. aureus and MRSA.
• Andrographis paniculata water extract also demonstrated activity against S. aureus and MRSA.
• Andrographis paniculata and Piper sarmentosum showed activity against Pseudomonas aeruginosa, with Andrographis paniculata being the most potent (MIC of 2 g/disc).

Conclusions:

• Several Malaysian medicinal plants, notably Andrographis paniculata, possess significant antibacterial potential against Gram-positive bacteria.
• Further research is warranted to isolate active compounds and explore their therapeutic applications.
• This study supports the traditional use of these plants and provides a basis for developing new antimicrobial agents.