Anti-Human Coronavirus Oc43 Activity Of Andrographolide And Deep Eutectic Solvent Extracts Of  Andrographis Paniculata  (Burm. F.) Nees

Background: Andrographis paniculata (Burm. f.) Nees has potential for treating infections caused by coronaviruses. However, the conventional dosage forms of A. paniculata were bulky and required several units with a high volume to get a therapeutic dose.Hypothesis/Purpose         Deep eutectic solvents (DES), as environmentally friendly and sustainable alternative solvents for extraction, might be useful to improve the dosage. However, the complexity of A. paniculata components is a critical factor for its quality control. Beside standardization of andrographolide, anti-human coronavirus OC43 activity might be a suitable bioassay for evaluating the quality of A. paniculata. Methods: This study evaluated and compared the in vitro anti-human coronavirus OC43 (HCoV-OC43) activity among various standardization A. paniculata extracts and andrographolide. The standardization of andrographolide and the antiviral activity were performed using UV-HPLC and a bioassay in HCT-8 colon cells, respectively. Results:  Methanol and five acidic DES (containing malic acid or citric acid) extracts of A. paniculataexerted anti-HCoV-OC43 activity. The antiviral activity had a moderately strong positive linear relationship (r2 = 0.74) with the andrographolide content. Although the methanol extract contained the highest andrographolide content (2.34 mg/mL), its anti-HCoV-OC43 activity was lower than that of DES extracts containing lower andrographolide levels (0.92-1.46 mg/mL).  Conclusion: The results suggested that acidic DES were capable of extracting andrographolide and antivirals from A. paniculata. The antiviral activity of A. paniculata extracts was the result of a complex combination of compounds. As a result, the quality of A. paniculata extracts in terms of in vitroantiviral potential did not have a very strong positive linear relationship (r2 < 0.8) with the andrographolide level in the extract. In other words, the anti-HCoV-OC43 test would be an interesting tool to provide a different kind of quality evaluation result for the complex A. paniculata extract.