Medicinal plants are considered the reservoir of diverse therapeutic agents and have been traditionally employed worldwide to heal various ailments for several decades. Silymarin is a plant-derived mixture of polyphenolic flavonoids originating from the fruits and akenes of Silybum marianum and contains three flavonolignans, silibinins (silybins), silychristin and silydianin, along with taxifolin. Silybins are the major constituents in silymarin with almost 70–80% abundance and are accountable for most of the observed therapeutic activity. Silymarin has also been acknowledged from the ancient period and is utilized in European and Asian systems of traditional medicine for treating various liver disorders. The contemporary literature reveals that silymarin is employed significantly as a neuroprotective, hepatoprotective, cardioprotective, antioxidant, anti-cancer, anti-diabetic, anti-viral, anti-hypertensive, immunomodulator, anti-inflammatory, photoprotective and detoxification agent by targeting various cellular and molecular pathways, including MAPK, mTOR, β-catenin and Akt, different receptors and growth factors, as well as inhibiting numerous enzymes and the gene expression of several apoptotic proteins and inflammatory cytokines. Therefore, the current review aims to recapitulate and update the existing knowledge regarding the pharmacological potential of silymarin as evidenced by vast cellular, animal, and clinical studies, with a particular emphasis on its mechanisms of action.

Cancer is a major burden of disease globally. Each year, tens of millions of people are diagnosed with cancer worldwide, and more than half of the patients eventually die from it. Significant advances have been noticed in cancer treatment, but the mortality and incidence rates of cancers are still high. Thus, there is a growing research interest in developing more effective and less toxic cancer treatment approaches. Curcumin (CUR), the major active component of turmeric (Curcuma longa L.), has gained great research interest as an antioxidant, anticancer, and anti-inflammatory agent. This natural compound shows its anticancer effect through several pathways including interfering with multiple cellular mechanisms and inhibiting/inducing the generation of multiple cytokines, enzymes, or growth factors including IκB kinase β (IκKβ), tumor necrosis factor-alpha (TNF-α), signal transducer, and activator of transcription 3 (STAT3), cyclooxygenase II (COX-2), protein kinase D1 (PKD1), nuclear factor-kappa B (NF-κB), epidermal growth factor, and mitogen-activated protein kinase (MAPK). Interestingly, the anticancer activity of CUR has been limited primarily due to its poor water solubility, which can lead to low chemical stability, low oral bioavailability, and low cellular uptake. Delivering drugs at a controlled rate, slow delivery, and targeted delivery are other very attractive methods and have been pursued vigorously. Multiple CUR nanoformulations have also been developed so far to ameliorate solubility and bioavailability of CUR and to provide protection to CUR against hydrolysis inactivation. In this review, we have summarized the anticancer activity of CUR against several cancers, for example, gastrointestinal, head and neck, brain, pancreatic, colorectal, breast, and prostate cancers. In addition, we have also focused on the findings obtained from multiple experimental and clinical studies regarding the anticancer effect of CUR in animal models, human subjects, and cancer cell lines.

Alzheimer’s disease (AD) is a gradually growing irreversible illness of the brain that almost affects every fifth person (aged > 80 years) in the world. World Health Organization (WHO) also revealed that the prevalence of this disease will enhance (upto double) significantly upto 2030. The poor cholinergic transmission at the synapse is considered to be one of the main reasons behind the progression and occurrence of this disorder. Natural inhibitors of acetylcholine (ACh) such as galanthamine and rivastigmine are used commercially in the treatmentof AD. The biomolecules such assesquiterpenes, possess a great structural diversity and are responsible for a plethora of pharmacological properties. The potential of various sesquiterpenes as anticholinesterase has been reviewed in this article. For this purpose, the various databases, mainly PubMed, Scopus, and Web of Science were investigatedwith different keywords such as “sesquiterpenes+acetylcholinesterase” and “sesquiterpenes+cholinesterase+inhibitors” in the surveyed time frame (2010–2020). A vast literature was evident in the last decade, which affirms the potential of various sesquiterpenes in the improvement of cholinergic transmission by inhibiting the AChE. After data analysis, it was found that 12 compounds out of a total of 58 sesquiterpenes were reported to possess IC₅₀ < 9 μM and can be considered as potential candidates for the improvement of learning and memory. Sesquiterpene is an important category of terpenoids, found to possess a large spectrum of biological activities. The outcome of the review clearly states that sesquiterpenes (such as amberboin, lipidiol, etc.) from herbs could offer fresh, functional compounds for possible prevention and treatment of AD.

The goal of current research was to develop a new form of effective drug, curcumin-loaded solid lipid nanoparticles (Cur-SLNs) and test its efficacy in the treatment of lung cancer. Different batches of SLNs were prepared by the emulsification–ultrasonication method. For the optimization of formulation, each batch was evaluated for particle size, polydispersity index (PI), zeta potential (ZP), entrapment efficiency (EE) and drug loading (DL). The formulation components and process parameters largely affected the quality of SLNs. The SLNs obtained with particle size, 114.9 ± 1.36 nm; PI, 0.112 ± 0.005; ZP, −32.3 ± 0.30 mV; EE, 69.74 ± 2.03%, and DL, 0.81 ± 0.04% was designated as an optimized formulation. The formulation was freeze-dried to remove excess water to improve the physical stability. Freeze-dried Cur-SLNs showed 99.32% of drug release and demonstrated a burst effect trailed by sustained release up to 120 h periods. The erythrocyte toxicity study of Cur-SLNs and its components demonstrated moderate hemolytic potential towards red blood cells (RBCs). The cytotoxic potential of the formulation and plain curcumin was estimated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay against A549 cell line. After 48 h of incubation, Cur-SLNs demonstrated more cytotoxicity (IC₅₀ = 26.12 ± 1.24 µM) than plain curcumin (IC₅₀ = 35.12 ± 2.33 µM). Moreover, the cellular uptake of curcumin was found to be significantly higher from Cur-SLNs (682.08 ± 6.33 ng/µg) compared to plain curcumin (162.4 ± 4.2 ng/µg). Additionally, the optimized formulation was found to be stable over the period of 90 days of storage. Hence, curcumin-loaded SLNs can be prepared using the proposed cost effective method, and can be utilized as an effective drug delivery system for the treatment of lung cancer, provided in vivo studies warrant a similar outcome.

Ageratum conyzoides L. (Family—Asteraceae) is an annual aromatic invasive herb, mainly distributed over the tropical and subtropical regions of the world. It owns a reputed history of indigenous remedial uses, including as a wound dressing, an antimicrobial, and mouthwash as well as in treatment of dysentery, diarrhea, skin diseases, etc. In this review, the core idea is to present the antifungal potential of the selected medicinal plant and its secondary metabolites against different fungal pathogens. Additionally, toxicological studies (safety profile) conducted on the amazing plant A. conyzoides L. are discussed for the possible clinical development of this medicinal herb. Articles available from 2000 to 2020 were reviewed in detail to exhibit recent appraisals of the antifungal properties of A. conyzoides. Efforts were aimed at delivering evidences for the medicinal application of A. conyzoides by using globally recognized scientific search engines and databases so that an efficient approach for filling the lacunae in the research and development of antifungal drugs can be adopted. After analyzing the literature, it can be reported that the selected medicinal plant effectively suppressed the growth of numerous fungal species, such as Aspergillus, Alternaria, Candida, Fusarium, Phytophthora, and Pythium, owing to the presence of various secondary metabolites, particularly chromenes, terpenoids, flavonoids and coumarins. The possible mechanism of action of different secondary metabolites of the plant against fungal pathogens is also discussed briefly. However, it was found that only a few studies have been performed to demonstrate the plant’s dosage and safety profile in humans. Considered all together, A. conyzoides extract and its constituents may act as a promising biosource for the development of effective antifungal formulations for clinical use. However, in order to establish safety and efficacy, additional scientific research is required to explore chronic toxicological effects of ageratum, to determine the probability of interactions when used with different herbs, and to identify safe dosage. The particulars presented here not only bridge this gap but also furnish future research strategies for the investigators in microbiology, ethno-pharmacology, and drug discovery.

Cancer is a major global concern. Despite considerable advancements in cancer therapy and control, there are still large gaps and requirements for development. In recent years, various naturally occurring anticancer drugs have been derived from natural resources, such as alkaloids, glycosides, terpenes, terpenoids, flavones, and polyphenols. Plant-derived substances exhibit their anticancer potential through antiproliferative activity, cytotoxicity, apoptosis, angiogenesis and cell cycle arrest. Natural compounds can affect the molecular activity of cells through various signaling pathways, like the cell cycle pathway, STAT-3 pathway, PI3K/Akt, and Ras/MAP-kinase pathways. Capsaicin, ouabain, and lycopene show their anticancer potential through the STAT-3 pathway in breast, colorectal, pancreatic, lung, cervical, ovarian and colon cancers. Epigallocatechin gallate and emodin target the JNK protein in skin, breast, and lung cancers, while berberine, evodiamine, lycorine, and astragalin exhibit anticancer activity against breast, liver, prostate, pancreatic and skin cancers and leukemia through the PI3K/Akt and Ras/MAP-kinase pathways. In vitro/in vivo investigations revealed that secondary metabolites suppress cancer cells by causing DNA damage and activating apoptosis-inducing enzymes. After a meticulous literature review, the anti-cancer potential, mode of action, and clinical trials of 144 bioactive compounds and their synthetic analogues are included in the present work, which could pave the way for using plant-derived bioactives as anticancer agents.