Antitumor and antioxidant effects of Clinacanthus nutans Lindau in 4 T1 tumor-bearing mice

A new isopimarane-type diterpene with anti-inflammatory activity from the Clinacanthus nutans

A new isopimarane-type diterpene clinacanoid A (1) together with seven known terpenoids (2-8) were obtained from the Clinacanthus nutans. Their structures were elucidated based on extensive spectroscopic analysis (NMR, HR-ESI-MS), and the absolute configuration of 1 was established based on single crystal X-ray diffraction. The inhibitory activity of all the compounds on NO production in lipopolysaccharide-induced (LPS) mouse leukemic monocyte macrophage RAW264.7 cells was evaluated. Among them, compounds 1 and 3 showed potential anti-inflammatory activities, with IC50 values of 13.3 ± 0.3 and 12.4 ± 0.4 μM, respectively.

Antiviral and Immunomodulatory Activities of Clinacanthus nutans (Burm. f.) Lindau

Clinacanthus nutans (Burm. f.) Lindau has been used as a traditional herbal medicine for treating snake bites, scalds, burns, and viral and bacterial infections. It has been attracting an increasing amount of attention because of its biological activities, including its antidiabetic, antioxidant, antibacterial, anticancer, anti-inflammatory, antiviral, and immunoregulatory activities. Here, we conducted a panoramic survey of the literature regarding the immunoregulatory, anti-inflammatory, and antiviral activities of C. nutans. We discovered that C. nutans extracts have virucidal activities against herpes simplex virus types 1 and 2, varicella-zoster virus, cyprinid herpesvirus 3, porcine reproductive and respiratory syndrome virus, mosquito-borne chikungunya virus, and potentially SARS-CoV-2; such activities likely result from C. nutans interfering with the entry, penetration, infection, and replication of viruses. We also reviewed the phytochemicals in C. nutans extracts that exhibit anti-inflammatory and immunoregulatory activities. This updated review of the antiviral, anti-inflammatory, and immunoregulatory activities of C. nutans may guide future agricultural practices and reveal clinical applications of C. nutans.

Crosstalk between fatty acid metabolism and tumour-associated macrophages in cancer progression

Over the last few decades, cancer has been regarded as an independent and self sustaining progression. The earliest hallmarks of cancer comprise of sustaining proliferative signalling, avoiding growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, and activating invasion and metastasis. Nonetheless, two emerging hallmarks are being described: aberrant metabolic pathways and evasion of immune destruction. Changes in tumour cell metabolism are not restricted to tumour cells alone; the products of the altered metabolism have a direct impact on the activity of immune cells inside the tumour microenvironment, particularly tumour-associated macrophages (TAMs). The complicated process of cancer growth is orchestrated by metabolic changes dictating the tight mutual connection between these cells. Here, we discuss approaches to exploit the interaction of cancer cells' abnormal metabolic activity and TAMs. We also describe ways to exploit it by reprogramming fatty acid metabolism via TAMs.

Exploring Clinacanthus nutans leaf different solvent extracts on antiproliferative effects induced metastasis through apoptosis and cell cycle against MCF-7 human breast cancer cell lines

Background

Medicinal herbs in Malaysia like Clinacanthus nutans (CN) traditionally are used in the treatment of various diseases and cancers. The present research was conducted to determine the effects of C. nutans leaf different solvent extracts on the human breast cancer cell lines (MCF-7). The antiproliferative growth and survival effects of dichloromethane CN leaf extracts (CNDCM), as well as the short- and long-term effects through metastasis, apoptosis and cell cycle effects, were observed. The chemical profiles were done to evaluate the properties of the CNDCM.

Results

The evaluation of GC–MS identified 16 major phytochemical compounds present in this extract with biological activities. Antiproliferative assay used is the SRB assay, which showed the CNDCM induced strong antiproliferative property compared with the other extracts, so its IC50 dose was selected for further testing with value 108 µg/mL at 72 h after exposure on MCF-7 and MCF-10A cell lines. The clonogenic survival effects of CNDCM in various concentrations (31.25, 62.5, 125, 250 and 500 µg/mL) inhibited the ability of MCF-7 cells to form colonies, and the metastasis result was indicated in an image of wound healing assay. Moreover, the CNDCM extract significantly induced apoptosis in all the cell cycle phases. Finally, the experiments with various extract concentrations on normal human breast cell lines showed no antiproliferative effects for all the extracts tested.

Conclusion

Among all the extracts of CN, the CNDCM extracts demonstrated the highest antiproliferative activity and survival against the MCF-7 cell lines tested.

Metabolomic Approach for Rapid Identification of Antioxidants in Clinacanthus nutans Leaves with Liver Protective Potential

Antioxidants are currently utilized to prevent the occurrence of liver cancer in non-alcoholic fatty liver disease (NAFLD) patients. Clinacanthus nutans possesses anti-oxidative and anti-inflammatory properties that could be an ideal therapy for liver problems. The objective of this study is to determine the potential antioxidative compounds from the C. nutans leaves (CNL) and stems (CNS). Chemical- and cell-based antioxidative assays were utilized to evaluate the bioactivities of CNS and CNL. The NMR metabolomics approach assisted in the identification of contributing phytocompounds. Based on DPPH and ABTS radical scavenging activities, CNL demonstrated stronger radical scavenging potential as compared to CNS. The leaf extract also recorded slightly higher reducing power properties. A HepG2 cell model system was used to investigate the ROS reduction potential of these extracts. It was shown that cells treated with CNL and CNS reduced innate ROS levels as compared to untreated controls. Interestingly, cells pre-treated with both extracts were also able to decrease ROS levels in cells induced with oxidative stress. CNL was again the better antioxidant. According to multivariate data analysis of the 1H NMR results, the main metabolites postulated to contribute to the antioxidant and hepatoprotective abilities of leaves were clinacoside B, clinacoside C and isoschaftoside, which warrants further investigation.

A Narrative Review on the Phytochemistry, Pharmacology and Therapeutic Potentials of Clinacanthus nutans (Burm. f.) Lindau Leaves as an Alternative Source of Future Medicine

The application of natural products and supplements has expanded tremendously over the past few decades. Clinacanthus nutans (C. nutans), which is affiliated to the Acanthaceae family, has recently caught the interest of researchers from the countries of subtropical Asia due to its medicinal uses in alternative treatment for skin infection conditions due to insect bites, microorganism infections and cancer, as well as for health well-being. A number of bioactive compounds from this plant's extract, namely phenolic compounds, sulphur containing compounds, sulphur containing glycosides compounds, terpens-tripenoids, terpens-phytosterols and chlorophyll-related compounds possess high antioxidant activities. This literature search yielded about one hundred articles which were then further documented, including the valuable data and findings obtained from all accessible electronic searches and library databases. The promising pharmacological activities from C. nutans leaves extract, including antioxidant, anti-cancer, anti-viral, anti-bacterial, anti-fungal, anti-venom, analgesic and anti-nociceptive properties were meticulously dissected. Moreover, the authors also discuss a few of the pharmacological aspect of C. nutans leaves extracts against anti-hyperlipidemia, vasorelaxation and renoprotective activities, which are seldom available from the previously discussed review papers. From the aspect of toxicological studies, controversial findings have been reported in both in-vitro and in-vivo experiments. Thus, further investigations on their phytochemical compounds and their mode of action showing pharmacological activities are required to fully grasp both traditional usage and their suitability for future drugs development. Data related to therapeutic activity and the constituents of C. nutans leaves were searched by using the search engines Google scholar, PubMed, Scopus and Science Direct, and accepting literature reported between 2010 to present. On the whole, this review paper compiles all the available contemporary data from this subtropical herb on its phytochemistry and pharmacological activities with a view towards garnering further interest in exploring its use in cardiovascular and renal diseases.

Osteogenic Activity of Lupeol Isolated from Clinacanthus nutans Lindau: Activity and Mode of Action

Clinacanthus nutans Lindau has been traditionally used for healing of bone fragility, but the mechanism of actions has not been clarified yet. In this study, the bone regeneration activity of lupeol derived from C. nutans was assessed using an in vitro model of osteoblast cells MC3T3-E1. The finding revealed that the compound was not significantly toxic to osteoblast cells at concentration of ≤40 μg/mL. Lupeol demonstrated the osteogenic activity through enhancement of alkaline phosphatase (ALP) of osteoblast cells up to 31.2%, 21%, and 12% at concentrations of 5, 10, and 20 µg/mL, respectively ( $p$  < 0.05). Besides, the mineralization activity was increased up to 170, 230, 185, and 117% at concentration of 5, 10, 20, and 40 μg/mL, respectively ( $p$  < 0.05). The marker genes related to osteoblast differentiation evaluated on the expression level in the presence of lupeol, including collagen I (col 1), osteopontin (opn), osterix (osx), and runx2, showed upregulated expression in all the test genes ( $p$  < 0.05). The Western blot analysis demonstrated a clear effect of lupeol on expression of p38/p-p38, and ERK/p-ERK proteins involved in the MAPK signaling pathway. Thus, lupeol isolated from C. nutans exhibited the osteogenic activity by enhancing expression of important markers of osteogenesis, as well as affected the MAPK signaling pathway relating to osteoblast differentiation. This is the first report on the detailed mechanism of action of lupeol on bone regeneration and also explains for the traditional use of this medicinal plant for bone healing.

Volatile Profiling Aided in the Isolation of Anti-Proliferative Lupeol from the Roots of Clinacanthus nutans (Burm. f.) Lindau

Isolation of anti-proliferative compounds from plants is always hindered by the complexities of the plant’s nature and tedious processes. Clinacanthus nutans (Burm. f.) Lindau is a medicinal plant with reported anti-proliferative activities. Our study aimed to isolate potential anti-proliferative compounds present in C. nutans plant. To start with, for our study, we came up with a strategy by first profiling the volatile compounds present in the leaf, stem and root of C. nutans using GC-MS. Comparing the plant’s volatile profiles greatly narrowed down our target of study. We decided to start with the isolation and characterization of a pentacyclic terpenoid, i.e., lupeol from the roots of C. nutans, as this compound was found to present abundantly in the roots compared to the leaf or stem. We developed a simple maceration and re-crystallization method, without the necessity to go through the fractionation or column chromatography for the isolation of lupeol. Characterizations of the isolated compound identified the compound as lupeol. The anti-proliferative activity of the isolated lupeol was further investigated against the MCF-7 cell line, which showed comparable anti-proliferative activity with the authentic lupeol and camptothecin. Our strategy to profile every part of the plant first, followed by selection of the most suitable plant part and targeted compound proved useful for further isolation and characterization bioactive compound from C. nutans.

Recent Advancement in Anticancer Activity of Clinacanthus nutans (Burm. f.) Lindau

Clinacanthus nutans is a traditional medicinal herb that is applied for the therapy of snake bites, skin infection, herpes infection, burns, scalds, dysentery, and diabetes. Clinacanthus nutans is also used to treat several cancers, including breast, cervical, colon, gastric, head and neck, liver, lung, pancreatic, and skin cancers, as well as lymphoma and leukemia; however, the underlying mechanisms of its anticancer activity remained undetermined. We searched PubMed and Google with key words “Clinacanthus nutans and cancer” and collected recent papers of Clinacanthus nutans with anticancer activity. We focused on the preparation, effects, and action mechanisms of Clinacanthus nutans extracts on various types of cancers. We hope that this mini review can help update our knowledge about active components, effects, and molecular mechanisms of extracts from this promising herb Clinacanthus nutans for ongoing studies and speed up its clinical application in the future.

Clinacanthus nutans Mitigates Neuronal Death and Reduces Ischemic Brain Injury: Role of NF-κB-driven IL-1β Transcription

Neuroinflammation has been shown to exacerbate ischemic brain injury, and is considered as a prime target for the development of stroke therapies. Clinacanthus nutans Lindau (C. nutans) is widely used in traditional medicine for treating insect bites, viral infection and cancer, due largely to its anti-oxidative and anti-inflammatory properties. Recently, we reported that an ethanol extract from the leaf of C. nutans could protect the brain against ischemia-triggered neuronal death and infarction. In order to further understand the molecular mechanism(s) for its beneficial effects, two experimental paradigms, namely, in vitro primary cortical neurons subjected to oxygen-glucose deprivation (OGD) and in vivo rat middle cerebral artery (MCA) occlusion, were used to dissect the anti-inflammatory effects of C. nutans extract. Using promoter assays, immunofluorescence staining, and loss-of-function (siRNA) approaches, we demonstrated that transient OGD led to marked induction of IL-1β, IL-6 and TNFα, while pretreatment with C. nutans suppressed production of inflammatory cytokines in primary neurons. C. nutans inhibited IL-1β transcription via preventing NF-κB/p65 nuclear translocation, and siRNA knockdown of either p65 or IL-1β mitigated OGD-mediated neuronal death. Correspondingly, post-ischemic treatment of C. nutans attenuated IκBα degradation and decreased IL-1β, IL-6 and TNFα production in the ischemic brain. Furthermore, IL-1β siRNA post-ischemic treatment reduced cerebral infarct, thus mimicking the beneficial effects of C. nutans. In summary, our findings demonstrated the ability for C. nutans to suppress NF-κB nuclear translocation and inhibit IL-1β transcription in ischemic models. Results further suggest the possibility for using C. nutans to prevent and treat stroke patients.

Alterations in Herbage Yield, Antioxidant Activities, Phytochemical Contents, and Bioactive Compounds of Sabah Snake Grass (Clinacanthus Nutans L.) with Regards to Harvesting Age and Harvesting Frequency

Sabah snake grass or Clinacanthus nutans has drawn public interest having significant economic benefits attributable to the presence of phytochemicals and several interesting bioactive constituents that may differ according to harvesting age and harvesting frequency. The current study was aimed to evaluate the effect of harvesting age and harvesting frequency towards herbal yield, antioxidant activities, phytochemicals synthesis, and bioactive compounds of C. nutans. A factorial randomized completely block design with five replications was used to illustrate the relationship between herbal yield, DPPH (2, 2-diphenyl-1-picrylhydrazyl) and ferric reducing antioxidant power (FRAP) assays, total phenolic and flavonoid content affected by harvesting age (week 8, 12, and 16 after transplanting), and harvesting frequency (harvest 1, 2, and 3). The bioactive compounds by HPLC were also determined to describe the interaction effect between both harvesting age and harvesting frequency. The yield, antioxidant activities, and phytochemical contents were gradually increased as the plant grew, with the highest recorded during week 16. However, the synthesis and activities of phytochemicals were reduced in subsequent harvests despite the increment of the herbal yield. All bioactive compounds were found to be influenced insignificantly and significantly by harvesting age and harvesting frequency, respectively, specifically to shaftoside, iso-orientin, and orientin. Among all constituents, shaftoside was the main compound at various harvesting ages and harvesting frequencies. These results indicated that harvesting at week 16 with 1st harvest frequency might enhance the yield while sustaining the high synthesis of polyphenols and antioxidant activities of C. nutans.