Pharmacognostic and Lactogenic Studies of the Leaves of Stachytarpheta Jamaicensis (l.) Vahl (Verbenaceae)

Abstract

Based on the ethnomedicinal use and belief that Stachytarpheta jamaicensis (SJ) can increase milk supply in lactating women, experimental studies were carried out to determine the effect of crude methanol extract (CME) and fractions of SJ leaves on serum PRL levels. The pharmacognostic standards, preliminary phytochemical analysis and acute toxicity study were also carried out. The fresh leaves were collected, cleaned, air-dried and pulverized. A photomicroscope was used in the qualitative microscopic recognition of the characteristic cell types and cell contents present in the powdered leaf. The quantitative microscopy of the leaf of SJ showed the values of palisade ratio, stomata number, stomata index, vein-islet number and vein termination number to be 4.42 ± 2.53, (105.67 ± 2.73, 277 ± 17.08), (28.00 ± 2.31, 21.00 ± 2.51), 15.67 ± 0.66 and 3.50 ± 0.00 respectively. For the analytical standards; 11.85 ±0.06, 2.17 ± 0.00, 8.80 ± 0.14, 2.04 ± 0.02, 2.51 ± 0.15, 4.85 ±0.22 and 4.30 ± 0.02 were obtained for total ash, water soluble ash, sulphated ash, acid insoluble ash, alcohol soluble extractive value, water soluble extractive value and moisture content respectively. The extraction process yielded 19.31 % W/W of the CME while the fractionation process yielded 36.70 % W/W, 10.00 % W/W, 26.15 % W/W and 27.80 % W/W of n-hexane fraction (HF), ethyl acetate fraction (EF), n-butanol fraction (BF) and water fraction (WF) respectively. The qualitative phytochemical analysis of the CME and fractions showed the presence of carbohydrates, reducing sugars, alkaloids, glycosides, saponins, tannins, flavonoids, resins, proteins, steroids and terpenoids. The acute toxicity (LD50) studies of CME, HF, EF, BF and WF were > 5000 mg/kg. The lactogenic activity studies of SJ leaves were carried out by checking the effect of their oral treatment on serum prolactin (PRL) secretion and release in rats.The CME of SJ produced an appreciable increase in serum PRL level when compared to the control in a dose-dependent manner. However, the ethyl acetate fraction exhibited the highest when compared to the control with potency greatly higher than the standard drug metoclopramide. The order of activity of the fractions is EF (800 mg/kg) > BF (800 mg/kg) > HF (800 mg/kg) > WF (800 mg/kg). The E2-primed groups showed high serum PRL concentration especially the groups receiving 800 mg/kg of the extract and ethyl acetate fraction respectively. The histological findings of the rat mammary gland tissues were shown to stimulate mammary gland development and differentiation of the lobulo-alveolar system from the lobular buds with milk secretion (proteinaceous materials) within the lumen of the alveoli and ducts. The largest tubulo-alveolar hyperplasia with were observed in the E2-primed groups receiving 800 mg/kg of extract and ethyl acetate fraction respectively. Stachytarpheta jamaicensis thus possesses galactogenic property which supports its traditional usage in lactating women with a wide therapeutic index.