Black pepper (Piper nigrum L.) is a climbing perennial plant in the Piperaceae family. Pepper has been known since antiquity for its use both as a medicine and a spice. It is particularly valued for its pungency attributed to its principal constituent -piperine. This review summarizes the information on the biological source of piperine, its extraction and isolation strategies, physicochemical properties, and pharmacological activity -analgesic, immunomodulatory, anti-depressive, anti-diarrheal, hepatoprotective, etc. The effect of piperine on biotransformation of co-administered drugs is also presented in this review, along with the mechanisms involved in its bioavailability-enhancing effect. Its important medicinal uses, including anti-hepatotoxic, anti-diarrheal, anti-depressive, analgesic, and immunomodulatory effects, besides many other traditional uses, are compiled. Based on an exhaustive review of literature, it may be concluded that piperine is a very promising alkaloid found in members of the Piperaceae family.

The present study is aimed at developing a synergistic combination to enhance learning and memory in Alzheimer’s patients with the help of eight common medicinal plants used in the AYUSH system. Aqueous and hydroalcoholic extracts of eight medicinal plants from the AYUSH system of medicine were prepared. These were subjected to in vitro anticholinesterase activity, to find out the combination index of synergistic combination. The synergistic combination and their individual extracts were subjected to total phenol, flavonoid and antioxidant activity estimation. Further, in vivo neurobehavioral studies in rats were carried out followed by TLC-MS-bioautographic identification of bioactive metabolites. Out of the sixteen extracts, aqueous extracts of Withania somnifera (L.) Dunal (WSA) and Myristica fragrans (L.) Dunal (MFA) were selected for the development of synergistic combination based on their IC50 value in vitro anticholinesterase assay. The synergistic combination inhibited the anticholinesterase activity significantly as compared to the individual extracts of WSA and MFA. The synergistic combination also showed more phenolic and flavonoid contents with potential antioxidant activity. The TLC-bioautography showed four white spots in WSA, signifying sitoindosides VII, VIII, quercetin, isopelletierine and Withanolide S as AChE inhibitory compounds while showing five white spots of anti-cholinesterase active metabolites identified as eugenol, methyl eugenol, myristic acid, galbacin and β-sitosterol in MFA. The observation of neurocognitive behavior in amnesia induced subjects manifested that both the synergistic combinations showed comparable results to that of standard piracetam, though the synergistic combination containing a higher concentration of WSA showed more appreciable results in ameliorating dementia in rats. The study suggests that the synergy based combination successfully enhanced memory and learning by abating free radical and acetylcholine levels, and increased learning and memory in rats, providing a strong rationale for its use in the treatment of dementia and Alzheimer’s disease.

Aim: The main objective of the study was to formulate, evaluate and perform an optimization study of chaulmoogra oil-loaded solid lipid nanoparticles (SLNs) based gel. Methods: The study involves isolation, identification, and quantification of hydnocarpic acid (HA), using high-performance thin-layer chromatography (HPTLC) and characterization using ultraviolet (UV), nuclear magnetic resonance (NMR), and mass spectroscopy (MS), and differential scanning calorimetry (DSC). Different concentration of assorted solid lipids and surfactants was used for the preparation of SLN gel with the improved transdermal application. Size distribution, entrapping efficiency, transmission electron microscopy (TEM), and percent yield were tested for the prepared SLN and the characterization of SLN gel was evaluated on the basis of in vitro diffusion study, stability studies, homogeneity, and skin irritancy test. Results: The amount of HA quantified in the oil sample was found to be 54.84% w/w. The percent yield and entrapment efficiency (EE) of HA SLNs were 96.176 ± 1.338% and 90.2 ± 0.5% respectively. The in vitro percent cumulative drug release was 80.89% for the developed SLN, the homogeneity test showed no grittiness, and the prepared gel was found to be effective as it shows no signs of erythema post-treatment of 10 days. The in vitro dissolution studies showed better results for SLN gel when compared to SLN suspension. Conclusions: The nano-gel could be a better option for the topical delivery of herbal drugs with improved bioavailability providing several benefits over conventional formulation.

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Tyrosinase is acopper-containing key substance in the pigmentation of mammalian hair and skin. Melanin synthesis is influenced by variety of extrinsic and internal variables, including hormone fluctuations, inflammation, ageing, and subsequent ultraviolet light exposure. Melasma, senile lentigines, freckles, and diminished colour are all undesirable side effects of excessive melanin production. The current review provides the pursuit of effective and safe tyrosinase inhibitors derived from medicinal plants, and ascribes an updated inferences on current practices. Commercially available tyrosinase inhibitors provide an even skin tone and are used clinically to treat hyperpigmentation and related disorders. This review focuses on the mechanism of melanogenesis and on experimentally verified potent and natural tyrosinase inhibitors. Bioactive compounds such as phenols, flavonoids, stilbenes, and a few traditional herbal formulations from the Indian system of medicine, have been used since long in India and subcontinents for the effective management of melanogenesis and related problems. Scientific information was gathered from different sources of databases such as PubMed, Google Scholar, Springer, Scopus, and Science Direct, as well as the literature found in medicinal plant books. This critically summarized review ensures to aid researchers and enterprises working on tyrosinase inhibitors and on conditions associated with melanogenesis, to get one-step solutions for identifying more safe and effective natural remedies.