College of Agriculture, Engineering
and Science (CAES)

PhD Graduate Investigates Chemical Compounds with Antibacterial Promise

Drug molecules which could contribute to combatting drug-resistant bacteria in an era of increasing antibiotic resistance were researched by Dr Neha Manhas for her PhD in Chemistry.

Supervised by Professor Neil Koorbanally, Manhas used the concept of molecular hybridisation to develop new Schiff bases of quinazoline-4-ones, testing their biological activity against a range of pathogenic bacterial strains.

The work is important because of the need to develop new drug molecules with more efficacy and novel mechanisms of action to target bacteria, as antibiotics are losing their potency against the defensive mechanisms adopted by bacterial species.

Manhas completed undergraduate studies in pharmacy at the Punjab Technical University in India, where she is a registered pharmacist and this experience fuelled her desire for a career in drug design and discovery. The experience she then gained while pursuing her Master’s degree in Chemistry at the Durban University of Technology also motivated her interest in this particular research topic.

Manhas’s results revealed several quinazoline-4-one couplings that produced promising compounds   with broad spectrum activity and selectivity against gram-negative bacterial strains, with one compound demonstrating considerably superior activity compared to the antibiotic ampicillin against the multidrug-resistant Klebsiella pneumoniae bacteria strain.

She also revealed the role of hydrophobic forces in stabilising these complexes, and the potential of these compounds to be developed further as anti-bacterial drugs. She also discovered where the fusion of quinazolin-4-one with quinoline, thiophene and indole moieties negatively influenced anti-bacterial activity.

Manhas believes this work, which is due to be published in peer-reviewed journals, will advance research in the direction of new drug compounds. She said that further derivatisation of these compounds holds promise for new potent anti-bacterial drugs with optimal pharmacological activity profiles.

Manhas hopes to continue her career as a researcher, and is currently investigating opportunities for postdoctoral research at UKZN.

Having moved from India to South Africa in 2013 to join her husband – senior lecturer in the School of Chemistry and Physics Dr Parvesh Singh – she found being far away from her family a challenge while completing her studies.  An additional pressure was that she had to adapt to acclimatising to a new culture, new people and languages, and a new environment, but she said South Africa was now like a second home to her. She credited the support of her husband, family and friends for ensuring her success in her studies and supporting her through the tireless work and hours she put into her research.

Manhas dedicated her PhD to her father, brother, sister-in-law and especially her mother, Ms Kiran Manhas, whose sacrifices and motivation, she said, enabled her to persevere to the point she is at now. She also thanked the Dunster family for their love, guidance, care and moral support in South Africa, saying their presence made adapting to life in the country relatively easy.

Words: Christine Cuénod

Photograph: Supplied