Biology and Ecology of Pharmaceutical Marine Tunicates

Ramasamy Santhanam, Santhanam Ramesh

• Publisher: CRC Press
• Year: 2019
• Print ISBN: 9780367337650, 9780367337650
• eBook ISBN: 9781000707991
• Edition: 1
• Topic: Biological Sciences
• Subtopic: Biology
• Index: Biological Sciences

The ocean is a source of unique natural products, mainly accumulated in living organisms. The c.4000 species of tunicates or sea squirts (Phylum, ?Chordata; Subphylum, ?Urochordata) are a high-potential yet under-studied source of bioactive compounds for pharmaceuticals. The secondary metabolites such as alkaloids isolated from these organisms have led to the discovery of an approved anti-tumor drug, anti-cancer drugs Yondelis® and Aplidin®, as well as many others in clinical trial.

There is an urgent need for more research on the bioactive compounds of marine tunicates and better knowledge about the identification and biology of these species. This is the first focused book to meet this need. The taxonomy, common name, global distribution, habitat, diagnostic features and pharmaceutical compounds (along with their activities) of 165 key species of tunicates are given, with high-quality illustrations.

Contributed by scientists of both Marine Biology and Pharmacy disciplines, this book will serve as a standard reference for researchers, teachers and students of Fisheries Science, Marine Biology, Life Sciences, Biotechnology, Natural Products, and Pharmacy, and as a valuable guide for pharmaceutical companies involved in the development of new drugs from marine organisms.

1

Introduction

The tunicates (Phylum, Chordata: Subphylum, Tunicata or Urochordata), the evolutionarily advanced invertebrate marine organisms, are said to be 500 million years old. This subphylum comprises about 3000 species that are exclusively marine, and it has three classes, viz. Ascidiacea (benthic and sessile tunicates), Thaliacea and Larvacea (or Appendicularia) (pelagic tunicates). Among these classes of tunicates, the class Ascidiacea assumes greater importance, nutritionally and pharmaceutically.

1.1 Ecology of Ascidians

Ascidians are exclusively marine, abundant in harbors, and can be found all over the world from near the surface to great depths. They exist below low-tide levels in protected areas with good water movement. The three orders within the class Ascidiacea, based on the structure of the adult branchial sac, are (1) Aplousobranchia (almost exclusively colonial), (2) Phlebobranchia and (3) Stolidobranchia (in both solitary and colonial forms).

1.2 Dietary Values of Ascidians

In parts of the world where ascidians are treated as seafood, the species eaten are all large—in fact, more than 10 cm long—and are easily collected in large quantities. The solitary stolidobranch ascidian species Pyura chilensis and Pyura praeputialis, which may reach lengths of 30 cm, are sold commercially both fresh and canned. In Europe, Microcosmus spp. are eaten raw and are sold in markets all over Mediterranean France, Spain, Italy, and Greece. The Japanese cook the bright red Halocynthia roretzi, and occasionally they eat the stalked Styela clava, which is also much appreciated in Korea (Monniot et al., 1991).

1.3 Harvest and Aquaculture of Ascidians

Several species of stolidobranchs are farmed for food in some parts of the world, mainly Japan and Korea. The species of ascidians that are wild-harvested and cultured are given in the following table.

Wild-harvested Species
Species	Harvesting Countries
Boltenia ovifera	Russia
Halocynthia aurantium	Korea, Russia
Microcosmus hartmeyeri	Japan
Microcosmus saba...

Table of contents

• Cover
• Half Title
• Series Page
• Title Page
• Copyright Page
• Contents
• Preface
• Authors
• Chapter 1: Introduction
• Chapter 2: Biology and Ecology of Marine Tunicates
• Chapter 3: Pharmaceutical Compounds and Activities of Marine Ascidians
• Compounds
• References
• Index