Discovery of procyanidin condensed tannins of (−)-epicatechin from Kratom, Mitragyna speciosa, as virucidal agents against SARS-CoV-2<sup>1</sup>
Issued Date
2024-07-01
Resource Type
ISSN
01418130
eISSN
18790003
Scopus ID
2-s2.0-85195816956
Journal Title
International Journal of Biological Macromolecules
Volume
273
Rights Holder(s)
SCOPUS
Bibliographic Citation
International Journal of Biological Macromolecules Vol.273 (2024)
Suggested Citation
Sureram S., Chutiwitoonchai N., Pooprasert T., Sangsopha W., Limjiasahapong S., Jariyasopit N., Sirivatanauksorn Y., Khoomrung S., Mahidol C., Ruchirawat S., Kittakoop P. Discovery of procyanidin condensed tannins of (−)-epicatechin from Kratom, Mitragyna speciosa, as virucidal agents against SARS-CoV-2<sup>1</sup>. International Journal of Biological Macromolecules Vol.273 (2024). doi:10.1016/j.ijbiomac.2024.133059 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/98862
Title
Discovery of procyanidin condensed tannins of (−)-epicatechin from Kratom, Mitragyna speciosa, as virucidal agents against SARS-CoV-2<sup>1</sup>
Corresponding Author(s)
Other Contributor(s)
Abstract
Kratom, Mitragyna speciosa, is one of the most popular herbs in the West and Southeast Asia. A number of previous works have focused on bioactive alkaloids in this plant; however, non-alkaloids have never been investigated for their biological activities. Antiviral and virucidal assays of a methanol leaf extract of Kratom, M. speciosa, revealed that a crude extract displayed virucidal activity against the SARS-CoV-2. Activity-guided isolation of a methanol leaf extract of Kratom led to the identification of B-type procyanidin condensed tannins of (−)-epicatechin as virucidal compounds against SARS-CoV-2. The fraction containing condensed tannins exhibited virucidal activity with an EC50 value of 8.38 μg/mL and a selectivity index (SI) value >23.86. LC-MS/MS analysis and MALDI-TOF MS identified the structure of the virucidal compounds in Kratom as B-type procyanidin condensed tannins, while gel permeation chromatograph (GPC) revealed weight average molecular weight of 238,946 Da for high molecular-weight condensed tannins. In addition to alkaloids, (−)-epicatechin was found as a major component in the leaves of M. speciosa, but it did not have virucidal activity. Macromolecules of (−)-epicatechin, i.e., procyanidin condensed tannins, showed potent virucidal activity against SARS-CoV-2, suggesting that the high molecular weights of these polyphenols are important for virucidal activity.