Taking root

When Navin Khanna contracted dengue a few years ago, he boiled parts of a climbing plant in water and drank the filtered liquid. The scientist had good reason to do so. Laboratory tests had proved that the extract of Cissampelos pareira had direct, antiviral activity against all four serotypes of dengue, a mosquito-borne viral disease with no proven treatment.

These tests were part of a public-private partnership between government laboratories such as the International Centre for Genetic Engineering and Biotechnology (ICGEB), where Khanna works, and the company Sun Pharma (via its acquisition of Ranbaxy Laboratories). Their aim was to scout for antiviral drugs derived from plants. The partnership eventually zeroed in on the Cocculus hirsutus, a creeper from the same plant family, for its more potent antiviral activity.

In November 2021, an original research article on the "potent anti-dengue activity" of phytopharmaceutical AQCH derived from the aqueous extract of C hirsutus by Khanna, researchers at the Council of Scientific & Industrial Research-Indian Institute of Integrative Medicine (CSIR-IIIM), and Sun Pharma, was published in the journal Frontiers in Microbiology.

In Khanna's lab, AQCH showed protective effects in primary and secondary-infected mouse models. It reduced viral loads in their small intestines and tamped down on pro-inflammatory cytokines and vascular leakage associated with severe disease. These results paved the way for further pre-clinical and clinical development of the drug. Phase two trials began enrolment in June last year, according to the central government's clinical trials registry.

AQCH is one of a clutch of compounds of plant origin being developed like any new chemical entity or pharmaceutical product. Khanna, who is the Arturo Falaschi Emeritus Scientist at ICGEB, believes that it is an example of what's possible if scientists and companies team up to marry India's rich diversity of medicinal flora, well-documented in traditional systems such as Ayurveda, with the tools and evidence-generating pathways of modern medicine.

"We are sitting on a goldmine," he says.