Hatchability of eggs of Haemonchus contortus with extracts of Caesalpinia echinata, Cajanus cajan, Dipteryx alata and Leucaena leucocephala in vitro

Parasites demonstrate resistance to major anthelmintic drugs. Studies with tanninipherous plants have been demonstrated their efficacy on gastrointestinal nematodes. The aim of this work was to evaluate the anthelmintic action of tanninipherous plants extracts on egg hatch assay (EHA) of Haemonchus contortus. The work was conducted at Institute of Animal Science (IZ/APTA/SAA) Nova Odessa/São Paulo/Brazil. The leaves of the following Fabaceae Caesalpinia echinata, Cajanus cajan, Dipteryx alata and Leucaena leucocephala cv. cunningham were collected at agrostological field at IZ/APTA/SAA, dried at 35 °C and ground. Their actives were extracted with a solution of acetone:water (70:30), followed by washings with dichloromethane and freeze-dried. The values of total tannins (TT) and condensed tannins (CT) were detected by methodology Makkar et al.[1]. The values found for TT and CT are shown in Table 1. The lyophilized extract was soluble in water at concentrations ranging from 50 mg/mL to 0.012 mg/mL to perform EHA. Data were analyzed by SAS/Probit to determine Lethal Concentration 50 (LC₅₀) with independent variables (dose) transformed by natural logarithms (log-dose). The lowest LC₅₀ was found for C. echinata to 0.17 mg/mL, followed by D. alata (4.63 mg/mL), L. leucocephala cv.cunningham (82.3 mg/mL) and C. cajan was not able to inhibit eggs to hatch. Among the plants evaluated the C. echinata was the most effective in inhibiting the hatchability of the eggs of H. contortus. Anthelmintic activity of C. echinata could not be attributed only to tannins.

Tab. 1: Values found for TT and CT.

Plants	D. alata	C. echinata	C. cajan	L. leucocephala (Cunningham)
*TT	109.10	95.90	91.61	74.96
**CT	199.76	58.79	241.13	55.66
TT: Total Tannins; CT: Condensed Tannins, *expressed values: grams of tannic acid/kg DM, **expressed values: grams of leucocyanidin/kg DM

Acknowledgements: FAPESP (2012/18379 – 3) and CNPq (476880/2012 – 2).

Keywords: Leguminosae, Parasites, sheep, Tannins

References:

MAKKAR, H.P.S.; BLUMMEL M.; BOROWY, N.K.; BECKER, K. Gravimetric determination of tannins and their correlation with chemical and protein precipitation methods. Journal of the Science of Food and Agriculture. v.61, p. 161 – 165. 1993.