Oxidative stress is a pathological condition occurring due to an imbalance between the oxidants and antioxidant defense systems in the body. Nuclear factor E2-related factor 2 (NRF2), encoded by the gene NFE2L2, is the master regulator of phase II antioxidant enzymes that protect against oxidative stress and inflammation. NRF2/ARE signaling has been considered as a promising target against oxidative stress-mediated diseases like diabetes, fibrosis, neurotoxicity, and cancer. The consumption of dietary phytochemicals acts as an effective modulator of NRF2/ARE in various acute and chronic diseases. In the present review, we discussed the role of NRF2 in diabetes, Alzheimer’s disease (AD), Parkinson’s disease (PD), cancer, and atherosclerosis. Additionally, we discussed the phytochemicals like curcumin, quercetin, resveratrol, epigallocatechin gallate, apigenin, sulforaphane, and ursolic acid that have effectively modified NRF2 signaling and prevented various diseases in both in vitro and in vivo models. Based on the literature, it is clear that dietary phytochemicals can prevent diseases by (1) blocking oxidative stress-inhibiting inflammatory mediators through inhibiting Keap1 or activating Nrf2 expression and its downstream targets in the nucleus, including HO-1, SOD, and CAT; (2) regulating NRF2 signaling by various kinases like GSK3beta, PI3/AKT, and MAPK; and (3) modifying epigenetic modulation, such as methylation, at the NRF2 promoter region; however, further investigation into other upstream signaling molecules like NRF2 and the effect of phytochemicals on them still need to be investigated in the near future.

Gymnema sylvestre is a plant that is enriched in bioactive compounds. In particular, gymnemic acids (GA) and phenolic compounds (PC) are pharmaceutically important. There is a commercial demand for naturally occurring bioactive compounds, but their availability is limited due to geographical and seasonal variations. The elicitation approach can enhance the biosynthesis of phytochemicals during in vitro culture of G. sylvestre. Here, to further improve gymnemic acid II (GA II) and phenolic compounds (PC) production by G. sylvestre, cell suspension cultures (CSC), which has attracted attention for the production of essential phytochemicals, was explored using copper oxide nanoparticles (CuO NPs). Callus was obtained on MS medium containing 2,4-dichlorophenoxyacetic acid, kinetin, phytoagar, and sucrose. Agar-free MS medium was used to initiate CSC, which was treated with three concentrations of CuO NPs (1, 3 or 5 mg/L). Treatment for 48 h with 3 mg/L CuO NPs resulted in the greatest yields of GA II, total phenolics, and flavonoids. The cultures also displayed pronounced antioxidant, antidiabetic, anti-inflammatory, antibacterial, antifungal, and anticancer activities. The use of CuO NPs (3 mg/L) significantly increased the production of GA II (nine-fold) and PC compared to unamended CSC. We propose that CSC and use of nanoparticles (NPs) as a new generation of elicitors, offer a suitable prospect for the production of bioactive compounds.

The importance of fruit-derived resveratrol (RES) in the treatment of various diseases has been discussed in various research publications. Those research findings have indicated the ability of the molecule as therapeutic in the context of in vitro and in vivo conditions. Mostly, the application of RES in in vivo conditions, encapsulation processes have been carried out using various nanoparticles that are made of biocompatible biomaterials, which are easily digested or metabolized, and RES is absorbed effectively. These biomaterials are non-toxic and are safe to be used as components in the biotherapeutics. They are made from naturally available by-products of food materials like zein or corn or components of the physiological system as with lipids. The versatility of the RES nanoparticles in their different materials, working range sizes, specificity in their targeting in various human diseases, and the mechanisms associated with them are discussed in this review.