Impact of microwaves on the extraction yield of phenolics, flavonoids, and triterpenoids from centella leaves: An approach toward digitized robust botanical extraction

Optimisation of Ultrasound-Assisted Extraction of Total Phenolics and Flavonoids Content from Centella asiatica

Centella asiatica (CA), known for its health-promoting properties, is rich in bioactive compounds. This study optimised ultrasound-assisted extraction (UAE) parameters to maximise total phenolic content (TPC) and total flavonoid content (TFC) using the response surface methodology (RSM). Ethanol concentration and solvent volume significantly influenced TPC and TFC yields (p < 0.0001), while ultrasonic power had nonsignificant effects (p < 0.05). Time showed no significant effect on TPC (p > 0.05) but influenced TFC due to flavonoids' sensitivity to degradation (p < 0.05). Variable interactions were negligible (p > 0.05). The relationship between responses (TPC and TFC) and independent parameters could be expressed as the quadratic models fitted with a Predicted R2 of 0.8263 for TPC and 0.9006 for TFC. Based on RSM, the optimal conditions-75% ethanol concentration, 87.5 W ultrasonic power, 30 min extraction time, and 20 mL solvent volume-yielded TPC and TFC values of 52.29 ± 1.65 mg/g and 43.71 ± 1.92 mg/g, closely aligning with model predictions at 95% confidence. Additionally, the optimal UAE condition provided asiaticoside of 37.56 ± 4.25 mg/g and madecassoside of 16.91 ± 1.28 mg/g. This study offers valuable insights into the factors influencing UAE efficiency, sustainability, and scalability for recovering bioactive compounds, underscoring its potential as a sustainable method for developing functional food ingredients from CA.

Therapeutic properties and pharmacological activities of asiaticoside and madecassoside: A review

Centella asiatica is an ethnomedicinal herbaceous species that grows abundantly in tropical and sub-tropical regions of China, India, South-Eastern Asia and Africa. It is a popular nutraceutical that is employed in various forms of clinical and cosmetic treatments. C. asiatica extracts are reported widely in Ayurvedic and Chinese traditional medicine to boost memory, prevent cognitive deficits and improve brain functions. The major bioactive constituents of C. asiatica are the pentacyclic triterpenoid glycosides, asiaticoside and madecassoside, and their corresponding aglycones, asiatic acid and madecassic acid. Asiaticoside and madecassoside have been identified as the marker compounds of C. asiatica in the Chinese Pharmacopoeia and these triterpene compounds offer a wide range of pharmacological properties, including neuroprotective, cardioprotective, hepatoprotective, wound healing, anti-inflammatory, anti-oxidant, anti-allergic, anti-depressant, anxiolytic, antifibrotic, antibacterial, anti-arthritic, anti-tumour and immunomodulatory activities. Asiaticoside and madecassoside are also used extensively in treating skin abnormalities, burn injuries, ischaemia, ulcers, asthma, lupus, psoriasis and scleroderma. Besides medicinal applications, these phytocompounds are considered cosmetically beneficial for their role in anti-ageing, skin hydration, collagen synthesis, UV protection and curing scars. Existing reports and experimental studies on these compounds between 2005 and 2022 have been selectively reviewed in this article to provide a comprehensive overview of the numerous therapeutic advantages of asiaticoside and madecassoside and their potential roles in the medical future.

Microwave-assisted extraction of polysaccharide from Cinnamomum cassia with anti-hyperpigmentation properties: Optimization and characterization studies

The anti-hyperpigmentation effect and tyrosinase inhibitory mechanism of cinnamon polysaccharides have not been reported. The current study focused on the extraction of polysaccharides from Cinnamomum cassia bark using microwave-assisted approach and optimization of the extraction process (i.e., microwave power, irradiation time and buffer-to-sample ratio) by Box-Behnken design to obtain a high yield of polysaccharides with high sun protection factor (SPF), anti-hyperpigmentation and antioxidant activities. The extracted pectic-polysaccharides had low molecular weight and degree of esterification. The optimal extraction process had polysaccharides characterized by (a) monophenolase inhibitory activity = 97.5 %; (b) diphenolase inhibitory activity = 99.4 %; (c) ferric reducing antioxidant power = 4.4 mM; (d) SPF = 6.1; (e) yield = 13.7 %. The SPF, tyrosinase inhibitory and antioxidant activities were primarily contributed by the polysaccharides. In conclusion, the polysaccharides from C. cassia could be an alternative therapeutic source for skin hyperpigmentation treatment.

Dietary Polyphenols: Extraction, Identification, Bioavailability, and Role for Prevention and Treatment of Colorectal and Prostate Cancers

Fruits, vegetables, and other edible plants in our diet have numerous health benefits, due to the bioactive compounds in these food items, including polyphenols. These plants are a rich and promising source of natural products and phytochemicals that can be used to treat and prevent numerous diseases and prevent the progression of cancer. Dietary polyphenols exhibit chemo-preventive and therapeutic effects against various ailments, including several types of cancer. The current study focuses on polyphenol’s traditional and advanced extraction methods, with supercritical extraction as a novel approach. It also deals with their identification, bioavailability, and role in preventing and treating colorectal and prostate cancers. Additionally, the article covers the literature that deals with the anticancer activities of polyphenols, as well as their potential use as anticancer agents.

Effect of natural leaf extracts as phytomedicine in curing geriatrics

Old age is viewed as an unavoidable, undesirable, and problem-ridden phase of life. As people age, they become more susceptible to disease and disability due to various factors like low immunity, decreased functionality of cells, DNA damage, higher incidence of inflammation, etc. Healthy aging is very important. The nutrition and health of the elderly is often neglected. Nutritional interventions could play an important part in the prevention of degenerative conditions of the elderly and an improvement of their quality of life. The medicinal properties of plants are always believed for its therapeutic effect and its efficiency in treating many without adverse effects. The role of phytomedicine in aging is very crucial as it possesses important bioactive compounds and constituents (such as polyphenols, flavonoids, phenolic acids, and others) which are considered to provide anti-aging properties as well as helps in reducing age-associated problems. Some natural leaves such as Moringa oleifera, curry leaves, guava leaves, green tea, olive leaves, Ginkgo biloba, thankuni leaves, grape leaves, vasaka leaves, and kulekhara leaves are found to have therapeutic effects against diseases like cancer, diabetes, immunosuppression, hepatic damage, and neurodegenerative disorders. Hence, this review aims at understanding the effectiveness of these natural products in curing the geriatric population and the mechanism by which the therapeutic effects are exerted by them.

Comparative Studies on Different Extraction Methods of Centella asiatica and Extracts Bioactive Compounds Effects on Antimicrobial Activities

The interest of consumers in using products containing phytochemicals derived from plants is growing day by day due to the shift of consumers' preferences from convenience to environmental sustainability. One plant utilized in many products is Centella asiatica, a herb commonly used in folk medicine, health supplements, and beauty products. Extraction of bioactive compounds from C. asiatica was performed using conventional methods and modern methods (e.g., microwave or ultrasound-assisted and subcritical water extraction). This review summarizes the variety of methods used to extract active compounds from C. asiatica, their influence on the bioactive compounds and antimicrobial activity in vitro and in vivo, and the safety and toxicology of C. asiatica extract.

Development of a colorless Centella asiatica (L.) Urb. extract using a natural deep eutectic solvent (NADES) and microwave-assisted extraction (MAE) optimized by response surface methodology

This study outlines a green process for Centella asiatica (L.) Urb. (CA) extraction. Natural deep eutectic solvents (NADESs) and microwave-assisted extraction (MAE) were combined to provide a high bioactive compound yield and high antioxidant activity. Among the NADESs evaluated, the combination of acetylcholine chloride : malic acid : water (1 : 2 : 2): water (40 : 60) was the best for extraction. These conditions provide high madecassoside (MS) (21.7 mg g-1 dry weight) and asiaticoside (AS) (12.7 mg g-1 dry weight) yields, with greater than 80% (v/v) EtOH (13.3 mg g-1 MS and 7.80 mg g-1 AS). In addition, the extracts from this process showed higher antioxidant activity (IC50 = 0.26 mg mL-1) than the CA aqueous EtOH and water extracts. Moreover, the color of the extract products was less green than that of the extracts prepared using EtOH and aqueous EtOH as solvents, which are suitable for cosmeceutical products. Response surface methodology (RSM) was used for MAE optimization. The ANOVA data from the central composition design (CCD) of RSM were fitted with quadratic models yielding acceptable R 2 (>0.93), adjusted R 2 (>0.87), predicted R 2 (>0.81), and nonsignificant lack of fit (p  > 0.05) values. The quadratic model was validated using optimal conditions (30 s, power 300 W, and a liquid to solid ratio 20 mL g-1), and the model validation showed more than 80% accuracy in both MS and AS yields. This research presented an effective green process for CA extraction, which resulted in an environmentally friendly CA extract requiring little energy consumption and no organic solvents.