An Update on Potential Antidepressants Derived from Marine Natural Products

INTRODUCTION

Depression is one of the most frequently occurring psychiatric disorders worldwide, affecting 121 million worldwide. World Health Organization (WHO) estimates that it is the leading cause of disability and the fourth leading contributor to the "global burden of diseases".

OBJECTIVE

Investigating and developing a drug with a novel benefit-risk profile is critical. Marine sources have been explored for their benefits as an alternative therapy for depression treatment. Numerous studies have shown that natural compounds containing peptides, alkaloids, polyphenols, diterpenes, glycosides, vitamins, and minerals from marine sources can potentially treat a wide range of disorders, including depression. Such phytoconstituents are known to reduce oxidative stress and neuroinflammation, regulate the synthesis or function of neurotransmitters such as glutamate and acetylcholinesterase, and aid in enhancing serotonin levels and nerve development.

METHODS

In this review study, a literature search was conducted using terms often used, including animal models of depression and their precise phases, marine sources, algae, sponges, and indole alkaloids. Additionally, databases were examined, including Scopus, Wiley, Elsevier, Google Scholar, and Web of Science. The Snowball technique was used to identify several articles about depression but correlated to marine sources in addition to database searches.

RESULTS

Current antidepressant medications have several negative side effects on the human body, including dry mouth, cardiovascular interference, gastrointestinal symptoms, genitourinary symptoms, hepatotoxicity, convulsions, and obesity. As a result, researchers can identify a wide range of potential targets for medications derived from marine sources. A combination of marinederived drugs and available treatments can be estimated to minimize the negative effects. So that these resources can be used as efficiently as possible, and various marine-derived substances can be studied for therapeutic efficacy.

CONCLUSION

This review focuses on the preclinical and clinical findings of marine-derived compounds with antidepressant properties that alter behavioural parameters and biochemical abnormalities, as well as their mechanism of action and in-vivo potential.

Biological activities of meroterpenoids isolated from different sources

Meroterpenoids are natural products synthesized by unicellular organisms such as bacteria and multicellular organisms such as fungi, plants, and animals, including those of marine origin. Structurally, these compounds exhibit a wide diversity depending upon the origin and the biosynthetic pathway they emerge from. This diversity in structural features imparts a wide spectrum of biological activity to meroterpenoids. Based on the biosynthetic pathway of origin, these compounds are either polyketide-terpenoids or non-polyketide terpenoids. The recent surge of interest in meroterpenoids has led to a systematic screening of these compounds for many biological actions. Different meroterpenoids have been recorded for a broad range of operations, such as anti-cholinesterase, COX-2 inhibitory, anti-leishmanial, anti-diabetic, anti-oxidative, anti-inflammatory, anti-neoplastic, anti-bacterial, antimalarial, anti-viral, anti-obesity, and insecticidal activity. Meroterpenoids also possess inhibitory activity against the expression of nitric oxide, TNF- α, and other inflammatory mediators. These compounds also show renal protective, cardioprotective, and neuroprotective activities. The present review includes literature from 1999 to date and discusses 590 biologically active meroterpenoids, of which 231 are from fungal sources, 212 are from various species of plants, and 147 are from marine sources such as algae and sponges.

Efficacy of risperidone for behavioral disorders in the elderly: a clinical observation

Standard antipsychotics are ineffective in some geriatric patients. In addition, they are not helpful for apathy and withdrawal. Studies have demonstrated that 5HT2 antagonists improve affective symptoms and anxiety; therefore, the efficacy of risperidone on agitation and withdrawal was considered. The literature on risperidone was reviewed, and the efficacy and limitations of risperidone observed in two geriatric patients, one with agitation and another with apathy and withdrawal. Risperidone proved to be effective in controlling disruptive behavior in geriatric patients. Combined antagonism of D2 and 5HT2 receptors might be effective in improving agitation and withdrawal. Risperidone, with both D2 and 5HT2 antagonistic properties, seems to have potential as an alternative agent in controlling agitation and withdrawal in geriatric patients. Caution and need for further observation is recommended.

New colorimetric method for the quantitative estimation of phospholipids without acid digestion

A unique colorimetric method for the quantitative determination of phospholipids that does not involve the acid digestion of the lipid is described. The phospholipids, after separation by thin-layer chromatography and elution from the silica gel, are heated with a chromogenic solution that is a modification of a spray reagent formulated by Vaskovsky and Kostetsky (1968, J. Lipid Res., 9: 396). The absorbance of the colored complex was read at 710 nm, and it followed Beer's law in the range of 1-10 micro g of phospholipid phosphorus.