Natural Products Journal, The - Volume 13, Issue 7, 2023

Native to the Southern Mediterranean region, Laurus nobilis L. (Family Lauraceae) is an evergreen shrub or tree found in warm climate regions with high rainfall. The leaves and essential oil of this plant have been widely used as condiments, spices, and flavoring agents in the culinary and food industries. The whole plant is also used for the traditional treatment of various diseases, including cough, asthma, hemorrhoids, rheumatic pain, diarrhea, intestinal, and cardiac diseases. Previous phytochemical investigation of this plant demonstrated the presence of a variety of secondary metabolites, especially terpenoids. The present study aims to critically analyze comprehensive literature on the pharmacological activity and mechanisms of action of terpenoids from Laurus nobilis L. The available information on the pharmacological activity of terpenoids from L. nobilis L. was obtained from textbooks, theses, as well as published articles through a variety of libraries and electronic databases. The present study demonstrated that L. nobilis is rich in terpenoids, with more than 200 entities identified in reported studies. Terpenoids from L. nobilis have shown a wide range of pharmacological activities, including anti-inflammatory, antidiabetic, antifungal, antibacterial, immunomodulatory, anticonvulsant, antioxidant and cytotoxic activities. The mechanisms of action of most of these terpenoids included the imbalance of the ionic permeability of the cell membrane (anti- inflammatory and antimicrobial activities), modulation of the effects of gamma-aminobutyric acid (GABA) nergic neurotransmission (anticonvulsant activity), and the inhibition of inflammatory responses, prevention of metastasis, and induction of apoptosis (cytotoxic effect), among others. Referring to in vitro studies, terpenoids of L. nobilis L. have shown a variety of biological activities. However, more cytotoxic and in vivo studies and detailed mechanisms of action of the bioactive terpenoids are recommended.

Background: Natural products have been used commonly in the pharmaceutical industry as well as traditional medicine due to their bioactive contents. Objective: The objective of this study is to isolate the polymethoxy flavones (PMFs) and evaluate the antiproliferative activity. Methods: The PMFs were extracted from Mentha dumetorum with boiling hot water and then partitioned with hexane and the extract was subjected to chromatographic techniques such as Sephadex LH-20, silica gel, and preparative TLC, and HPLC to isolate the compounds. The structures of isolated compounds were elucidated by spectroscopic techniques such as ¹H-NMR, ¹³C-NMR, LC-TOF-MS, and UV-Vis. The antiproliferative effects of isolated compounds were evaluated using a real-time cell analyzer–single plate (RTCA-SP) instrument against HeLa and HT29 cell lines. Results: The isolated PMFs were identified as xanthomicrol (1), 5-hydroxy-6,7,8,4'-tetrametoxy flavanone (2), 5-desmetil sinensetin (3), 5-demetil nobiletin (4), gardenin B (5), 5-hydroxy-6,7,8,3',4'- penta methoxy flavanone (6) and 5-hydroxy-6,7,4'-trimethoxy flavone (7). Compounds 2 and 5 were found to be the most active against both cell lines. Conclusion: The isolated compounds as well as the plant extract of Mentha dumetorum could be promising agents for the drug development process, especially drugs for cancer treatment. Moreover, isolation methods were developed for the corresponding compounds.

Haircare products with botanical origins and the absence of highly allergenic chemicals, such as parabens, petrochemicals, and silicones, have been considered more skin-friendly and ecofriendly to the environment. Recently, there has been a growing demand for these natural hair care products. Besides the perceived health benefits, many users also believe these botanical origin ingredients are generally milder, non-toxic, natural, and less likely to disrupt the hair and scalp's natural pH and oil balance. Garcinia mangostana has been known for centuries in traditional Asian medicine. α-Mangostin is the major xanthone present in G. mangostana. It exists abundantly in the fruit pericarp. Numerous activities have been reported on this plant and α-mangostin in hair care and scalp maintenance. Our review is the first to highlight the potential of G. mangostana pericarp and α-mangostin and the activities emphasized in hair care. This review thoroughly discussed five essential activities: antimicrobial, antioxidant, anti-inflammatory, hair rejuvenation (hair growth), and tanning.

Background: Hypericum heterophyllum has been used as a traditional medicine and includes significant bioactive compounds. Objective: To quantitatively determine the phenolic and flavonoid contents of Hypericum heterophyllum flowers and evaluate the antioxidant activity. Also, to present the activity-compound relationship. Methods: Flowers of H. heterophyllum Vent., endemic species for Turkey were collected from Yozgat-Turkey. H. heterophyllum flowers were extracted with methanol, ethanol, acetone, and chloroform individually. LC-ESI-MS/MS analysis for phytochemicals was carried out for each extract. Total phenolic and flavonoid content were carried out for each extract. The antioxidant activity was performed using DPPH•, ABTS•+, hydroxyl radical, and superoxide radical scavenging assays. Results: Chlorogenic acid was found as a major compound in all extracts. Among the extracts, methanol extract included the most phenolic compound. The methanol extract and acetone extract consisted of the most flavonoids. Acetone and ethanol extracts revealed the most DPPH and ABTS activity respectively. Acetone extract exhibited the highest hydroxyl radical and superoxide radical scavenging effect. Conclusion: Flowers of H. heterophyllum contain bioactive compounds and they revealed good antioxidant activity. Hence, H. heterophyllum flowers could be a promising agent for the pharmaceutical and food industries.

Globally, there are around 50 million Alzheimer's disease sufferers worldwide, a number that is expected to double every five years and reach 152 million by 2050. Traditional drugs for cognitive impairment are only palliative and do not cure the disease. Alzheimer's disease is characterised by memory and language loss, as well as difficulties with visual orientation and greater executive function. The present study aimed to examine various causes, mechanisms, and roles of different herbal components in the treatment of Alzheimer’s disease. Since ancient times, several different plants have been utilised to improve memory and treat various dementia-related issues. These anti-AD plants include a wide taxonomic range due to acetyl choline esterase inhibition, antioxidant capacity, neuroprotection, mitochondrial energy restoration, and/or precipitated protein clearance. Secondary metabolites of these medicinal plants may be used to treat AD. AADvac1 is an active vaccination that stimulates an immune response by attacking numerous critical epitopes in pathogenic tau variants, thereby preventing tau aggregation and reducing the development of neurofibrillary tangles. Herbal plants are widely used because of their perceived effectiveness, safety, and low cost. To summarise, the evidence supporting the use of herbal components is promising, but more work is needed.

Alkaloids are waste products of plant metabolic processes, containing at least one nitrogen atom in the heterocyclic ring. They serve a wide variety of physiological functions in humans and animals. Metabolism plays a central role in regulating the toxicity of various phytochemicals. Available literature of biological sources and metabolism study of pyrrolidine, pyrrolizidine, pyridine, quinoline, isoquinoline, phenanthrene, phenethylamine, indole, terpenoid, and aporphine groups of experimental plantsderived alkaloids were collected from the Google Scholar, PubMed/Medline, Science Direct, Scopus, Wiley Online Library, and Web of Science search engines. The literature reveals that hepatic microsomal enzymes such as monooxygenase and putative NADPH-FMN-reductase, carboxyl esterase, CYP2B6, CYP3A4, and CYP2D6 are primarily involved in the metabolism of alkaloids. This review may encourage natural product researchers to further research and develop new plant-derived alkaloidal drugs.

Background: Oxidative stress occurs when the cell's antioxidant defense system is insufficient. This can be corrected by active antioxidant substances, which help to eliminate the consequences of the damage caused or prevent the system from reaching the stress level. Objective: The actions of antioxidants can inhibit or delay tumor cells' appearance, delaying aging, and preventing other cellular damage resulting from the redox imbalance. Therefore, the present work aimed to research studies already published on Protium heptaphyllum (P. heptaphyllum) and its biological activities, mainly antioxidant effects once resulting from phenolic compounds, such as flavonoids, present in the plant. Methods: The methodology used was a literature review where information was collected from several studies related to P. heptaphyllum, oxidative stress, polyphenols, and flavonoids in databases, such as Scielo, PubMed, Google Scholar, LILACS, Chemical Abstract, ScienceDirect, among others in the period from 2002 to 2021. Results: The main studies carried out with metabolites of P. heptaphyllum demonstrated several biological activities such as antioxidant, gastroprotective, anti-inflammatory, analgesic, anxiolytic, antihyperglycemic, hyperlipidemic, among others. Although P. heptaphyllum has been little investigated by pharmacological studies, the results reported in this work may contribute to this plant species' chemical/ pharmacological knowledge. Therefore, the secondary metabolites present in the plant may become test targets in future clinical trials for the drug arsenal. Conclusion: It can be observed that P. heptaphyllum is a promising source of secondary compounds, mainly flavonoids.

Background: Exposure to arsenic through drinking water is a global health problem that causes multisystem toxicity, mainly by inducing oxidative stress and impairing cellular energy. Objective: We aimed to evaluate the effect of Quercus infectoria gall extract (Qi) against oxidative stress induced by sub acute exposure to arsenic. Methods: The plant galls were extracted with methanol and were used for the determination of total phenolic content using Folin-Cio calteu reagent. Male Wistar rats were randomly divided into 8 groups of 6 animals and treated for 30 days. Negative and positive control groups received, respectively, normal saline and sodium arsenite (5.5 mg/kg) by gavage. Treatment groups received three doses of Qi (200, 400, and 600 mg/kg/day) by intraperitoneal injection 2 h. after oral administration of normal saline or sodium arsenite (5.5 mg/kg) (As-Qi). After 30 days, all animals were anesthetized with ketamine/xylasine and 2 mL of blood was taken for measurement of total antioxidant capacity (TAC) using ferric reducing antioxidant power (FRAP), lipid peroxidation (measurement of malondialdehyde (MDA)) and protein carbonylation of plasma. Results: Total phenolic content of the plant was determined to be 5.78 ± 0.23 mg gallic acid equivalent/g dried extract. The results of pharmacological studies indicated that in arsenic treated animals, a significant decrease in TAC, increase in lipid peroxidation and protein carbonylation happens compared to control group. Co-administration of Qi (600 mg/kg) with arsenic significantly increased TAC compared with arsenic group (0.245 ± 0.007 versus 0.183 ± 0.027 for arsenic) (p < 0.05), while the serum MDA level (1.880 ± 0.499 versus 2.795 ± 0.112 for arsenic) and protein carbonylation were decreased in this group compared with arsenic treated animals (0.128 ± 0.007 versus 0.159 ± 0.009 for arsenic) (p < 0.01). In non-treated arsenic animals (NTAS), all three doses of Qi improved oxidative stress markers. Conclusion: Arsenic disrupt cellular antioxidant defense through overproduction of reactive oxygen species (ROS) and the Qi galls are able to revert some of these oxidant activities of arsenic. Previous studies have reported antioxidants in the plant and the present work can conclude that antioxidant effect of Qi is useful against happened oxidative stress in arsenic treated animals.