Hemoglobin Precipitation: An Index of In Vitro Vasoconstrictive Activities of Methanol Leaf Extracts of Croton megalocarpus Hutch and Lantana camara Linn

The function of innate hemostasis aids the body in bleeding control, preventing the loss of excessive amounts of blood following low-degree injuries. However, injuries of a higher degree may require extrinsic intervention to stop life-threatening blood loss. Astringent agents' actions result in mechanical constriction of small blood vessels and shrinkage of body tissues, thereby stopping blood loss. This enhances the primary phase of hemostasis, where vasoconstriction is the main mechanism at play during the initial response to injury. The effects of plant extracts on protein precipitation have been linked to blood vessel vasoconstriction. Traditionally, the leaves of Croton megalocarpus Hutch and Lantana camara Linn plants are used by communities living in Makueni County, Kenya, for peripheral bleeding control. However, the effects of extracts of both plants on hemoglobin precipitation have not been evaluated scientifically. In the current study, the activities of methanol extracts of C. megalocarpus (H.) and L. camara (L.) on blood protein precipitation were investigated. The leaves were harvested, cleaned, air-dried, milled, and extracted in absolute methanol before being concentrated into dry powders. A qualitative phytochemical screen revealed the presence of terpenoids, steroids, tannins, phenols, flavonoids, reducing sugars, cardiac glycosides, and carbohydrates in the methanol extract of C. megalocarpus (H.). The methanol extracts of L. camara (L.) contained cardiac glycosides, saponins, tannins, phenols, terpenoids, reducing sugars, and carbohydrates. The hemoglobin precipitation ability of various concentrations of extracts using mice samples was presented as relative astringency following the tannic acid external standard method. Methanol extracts C. megalocarpus (H.) and L. camara (L.) had significantly higher relative astringency compared with the normal control, indicating a protein precipitating activity. The relative astringency observed in both plant extracts is linked to the activity of tannins, phenols, flavonoids, and saponins detected during preliminary phytochemical screening.