Herbal immune-boosters: Substantial warriors of pandemic Covid-19 battle

Full article available here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7532351/

Current scenario depicts that the world has been clenched by the COVID-19 pandemic. Inevitably, public health and safety measures could be undertaken in order to dwindle the infection threat and mortality.

Moreover, to overcome the global menace there is an exigency for social distancing and quarantines. Since December, 2019, coronavirus, SARS-CoV-2 (COVID-19) has come into existence and up till now, the world is still in a state of shock. At this point in time, COVID-19 has entered a perilous phase, creating havoc among individuals, and this has been directly implied due to enhanced globalisation and the ability of the virus to acclimatize at all conditions.

Towards this effort, the present review discusses the vital concepts related to COVID-19, in terms of its origin, transmission, clinical aspects and diagnosis. However, here, we have formulated the novel concept hitherto, ancient means of traditional medicines or herbal plants to beat this pandemic.

Plant based-therapeutic approaches against COVID-19

The traditional medicines have been in general disregarded in the novel research and expansion of contemporary drugs due to the fact that their translational ability is commonly underrated. These medicines are considered vague in the context of their usage in non-western medical technologies (Yuan et al., 2016). A wide array of phytochemical components is extracted from a single herb that may function unaided or in amalgamation with other components to yield preferred pharmacological effects (Parasuraman et al., 2014). It has been frequently indicated that 70-80% of the people belonging to developing countries are directly dependent on herbal d for their primary healthcare in comparison to modern synthetic drugs (Hamilton, 2004).

The beneficial impact of the medicinal plants lies in their bioactive constituent's specifically secondary metabolites viz. steroids, alkaloids, diterpenes, triterpenes, aliphatics and glycosides etc. (Chikezie et al., 2015). The exploration for innovative phytochemical with antiviral bioactivity has frequently been substandard and inefficient due to adaptive viral resistance accompanied by viral latency and persistent infections in patients with compromised immunity (Sumithira et al., 2012). Most of the antiviral therapeutics modules are non-specific in their action towards viruses (Jiang et al. 2015). The progression in development of novel antiviral mediators is the foremost concern of the medical research at present. The antiviral bioactivities of plethora of medicinal plants plays a remarkable role in diverse stages of virus growth (Akram et al., 2018).

The traditional Indian medicines network is one of the oldest health modules since the human existence and plays a crucial role in combating and fulfilling the needs of the global healthcare system (Ravishankar and Shukla, 2007). These traditional practices include ayurveda, siddha, yoga and unani, homeopathy and naturopathy and they are lucratively practiced for healing varied infectious disorders (Gomathi et al., 2020). These modules employ plants, animal products and minerals for treatment of wide range of diseases (Tabuti et al., 2003). Approximately, twenty-five thousand plant based formulations and extracts have been used in folk medication in the south Asian subcontinents (Pundarikakshudu and Kanaki, 2019). Moreover, recently total medicinal plants in India were estimated to be 3000, nevertheless traditional ayurveda practioners use around 8000 varied species of plant for the treatments (Pundarikakshudu and Kanaki, 2019).

Recently, in India, it was suggested by the Ministry of AYUSH (Ayurvedic, Yoga and Naturopathy, Unani, Siddha and Homeopathy), to drink Kadha as a booster of immunity and lowering the tenderness caused during COVID-19 catastrophe (AYUSH Advisory, 2020). A Kadha is an extract prepared from less juicy or dry ingredients like spices and herbs. The Ministry of AYUSH with its conventional acquaintance has an extensive custom of maintenance of nation's health and its participation has augmented manifolds in this COVID-19 pandemic crisis (AYUSH Advisory, 2020).

All ayurvedic healthcare professional generally recommend classical ayurveda medicine, however AYUSH-64 a novel formulation prepared by CCRAS provides resistance against malaria and other fevers. The decoction of sunthi (Zingiber officinaleRoscoe.), lavanga (Syzygium aromaticum) and maricha (Piper nigrum) have been recommended to the healthy as well as COVID-19 infected person, as it provides support in the humoral and cell mediated responses and also lowers the air way hyper responsiveness and nasal congestions (Carrasco et al., 2009; Kim and Lee, 2009; Bui et al., 2019).

Various ayurvedic products and fatty acids in the form of ghee are implicated in the up-regulation of resistance. The resistance is enhanced in a pleiotropic manner and the bioactive compounds participate in various procedures of adaptive as well as innate immune responses (Shukla et al., 2014). Similarly, the bioactive constituent in Curcuma longa Linn. i.e. curumin, is identified to block cytokine release, specifically interleukin-1, interleukin-6, pro-inflammatory cytokines and tumor necrosis factor-α and is directed to be consumed with milk (Omara et al., 2010). Inhibition of the cytokine discharge is one of the prime clinical development associated with experimental modules of flu and other infectious diseases and have also been compared to COVID-19 where similar cytokine storm play an imperative role in transience (Sordillo and Helson, 2015). Moreover, AYUSH has recommended certain preventive and medicinal plants for prevention and prophylactic of COVID-19 including warm extracts of Tinospora cordifolia (advised for chronic fever), Andrograhis paniculata (advised for fever and cold), Cydonia oblonga, Zizyphus jujube and Cordia myxa (enhancing antioxidant, immune-modulatory, anti-allergic, smooth muscle relaxant, anti-influenza activity) and Arsenicum album 30 (found effective against SARS-CoV-2, immune-modulator). The symptomatic management of COVID-19 was suggested to be acquired from Agastya Haritaki (prevention of upper respiratory infections and Anuthaila (sesame oil drops) recommended to prevent respiratory infections (Vellingiri et al., 2020).

TCM clinical trials and studies indicate the amelioration of symptoms of mild to moderate COVID-19 infections. The seriously infected patients tormented from hypoxia, were competent to ease the symptoms including high fever, breathing problems and coughing (Toots et al., 2019). Furthermore, a report by Song et al. (2019) revealed the bioactive potential of extracts Sanctellaria baicalensis containing baicalin which is considered as one of the prime TCM herbal constituent as well as hesperetin a bioactive constituent present in tangerine peel, have been employed in curing the symptoms associated with COVID-19 (Panda et al., 2020). Another TCM medicine viz. Xuebijing Injections has been widely affirmed to lower the hazards of community-transmission of pneumonia as well as it reduces the time required for ventilating a severe patient (Song et al., 2019).

One of the commonly accepted traditional Chinese medicines is Kombucha, which is a concoction prepared from the culture of Acetobacter and yeast. This concoction is prepared in black tea and Chinese herbal extract comprised of liquorice, green tea, chrysanthemum and Grosvenor momordia, which acts as an effective probiotic (Greenwatt et al., 2000). Similar extract has been employed in treatment of foot and mouth disease virus. Moreover, their exist a wide array of reports suggesting utilization of herbal extracts in TCM such as extracts prepared from Azadirachta indica (Kumar and Navaratnam, 2013; Gupta et al., 2017), Camellia sinensis (Song et al., 2005; Kuzuhara et al., 2009; Li et al., 2015), Ocimum sanctum and Agremone mexicana (Varshney et al., 2013), Zingiber officinale (Shah and Krishnamurthy, 2013), Tinospora cordifolia (Shah and Krishnamurthy, 2013), Alium sativum (Kim et al., 2005; Wang et al., 2006) and Ocimum basilicum (Kubiça et al., 2014) etc. for their antimicrobial potential. A corroborative suggestion was made by Su et al. (2020), that traditional Chinese herb i.e. Exocarpium Citri grandis was found to be effective in preventing and treating COVID-19 pandemic. A novel approach to TCM is combination therapy in which the old traditional practices are mixed together to develop an effective formulation for treating various diseases. Combination treatment has been employed in suppression of viral hepatisis. Also liquid fermented broth of Ganoderma lucidum in combination with extract of Radix Sophorae flavescentis, was affirmed to be effective against hepatitis B virus. Another vital example is glycyrrhizin a bioactive compound isolated from Lycoris radiata shows a strong potential against anti-SARS-CoV activity (Li et al., 2005a,b).