Medicinal Herbs and Plants: Potential Treatment of Monogenean Infections in Fish

Abstract

Monogenean parasites are responsible for tremendous annual economic losses in both freshwater and marine aquaculture operations. These losses have led to the extensive deployment of chemical treatments, such as praziquantel and mebendazole, in an effort to manage infections from these parasites. While effective, the environmental side effects associated with these treatments are, however, concerning. In recent years, medicinal plants including rosemary (Rosmarinus officinalis), garlic (Allium sativum), ginger (Zingiber officinale), ashanti pepper (Piper guineense), peppermint (Mentha piperita), tea tree (Melaleuca alternifolia), bge seeds (Semen aesculin), and bupleurum chinense roots (Bupleuri chinensis) have demonstrated promising anthelmintic activity against monogenean infections in fish. Most of these plants have been applied to infected host as part of a bath treatment regime, with less attention being paid to their application as an oral treatment. There is also limited information on the bioavailability of compounds present in these natural remedies, into fish organs. As the majority of the aforementioned plants have some immunostimulatory effects on fish, many of these studies have examined the herbs potency on fish immune-physiological variables. In addition, the number of fish species involved with in vivo trials where anthelmintic activity or toxicity was examined is minimal, and most of the studies focused on only one species of fish. This review focuses the evidence for anthelmintic activity of medicinal plants in fish and discuss the gaps where further research is required.