Traditional use of plants against snakebite in Indian subcontinent: a review of the recent literature

Three finger toxins of elapids: structure, function, clinical applications and its inhibitors

The WHO lists snakebite as a "neglected tropical disease". In tropical and subtropical areas, envenoming is an important public health issue. This review article describes the structure, function, chemical composition, natural inhibitors, and clinical applications of Elapids' Three Finger Toxins (3FTX) using scientific research data. The primary venomous substance belonging to Elapidae is 3FTX, that targets nAChR. Three parallel β-sheets combine to create 3FTX, which has four or five disulfide bonds. The three primary types of 3FTX are short-chain, long-chain, and nonconventional 3FTX. The functions of 3FTX depend on the specific toxin subtype and the target receptor or ion channel. The well-known effect of 3FTX is probably neurotoxicity because of the severe consequences of muscular paralysis and respiratory failure in snakebite victims. 3FTX have also been studied for their potential clinical applications. α-bungarotoxin has been used as a molecular probe to study the structure and function of nAChRs (Nicotinic Acetylcholine Receptors). Acid-sensing ion channel (ASIC) isoforms 1a and 1b are inhibited by Mambalgins, derived from Black mamba venom, which hinders their function and provide an analgesic effect. α- Cobra toxin is a neurotoxin purified from Chinese cobra (Naja atra) binds to nAChR at the neuronal junction and causes an analgesic effect for moderate to severe pain. Some of the plants and their compounds have been shown to inhibit the activity of 3FTX, and their mechanisms of action are discussed.

Plant-Derived Toxin Inhibitors as Potential Candidates to Complement Antivenom Treatment in Snakebite Envenomations

Snakebite envenomations (SBEs) are a neglected medical condition of global importance that mainly affect the tropical and subtropical regions. Clinical manifestations include pain, edema, hemorrhage, tissue necrosis, and neurotoxic signs, and may evolve to functional loss of the affected limb, acute renal and/or respiratory failure, and even death. The standard treatment for snake envenomations is antivenom, which is produced from the hyperimmunization of animals with snake toxins. The inhibition of the effects of SBEs using natural or synthetic compounds has been suggested as a complementary treatment particularly before admission to hospital for antivenom treatment, since these alternative molecules are also able to inhibit toxins. Biodiversity-derived molecules, namely those extracted from medicinal plants, are promising sources of toxin inhibitors that can minimize the deleterious consequences of SBEs. In this review, we systematically synthesize the literature on plant metabolites that can be used as toxin-inhibiting agents, as well as present the potential mechanisms of action of molecules derived from natural sources. These findings aim to further our understanding of the potential of natural products and provide new lead compounds as auxiliary therapies for SBEs.

Perceptions, awareness on snakebite envenoming among the tribal community and health care providers of Dahanu block, Palghar District in Maharashtra, India

INTRODUCTION

India has remarkably the highest number of snakebite cases contributing to nearly 50% of the global snakebite deaths. Despite this fact, there is limited knowledge and awareness regarding the management practices for snakebite in the Indian population. The study aimed to explore the knowledge, awareness, and perception of snakes and snakebites, first aid, and treatment amongst the community and the frontline health workers in a tribal block of Dahanu, Maharashtra, India.

METHODS

A cross-sectional study was carried out from June 2016 to October 2018 in the Dahanu Block, Maharashtra. Perceptions, knowledge, awareness, and first-aid practices on the snakebites among the community were studied through focus group discussions (FGDs). Semi-structured questionnaires were used to assess the knowledge, awareness, and experience of the traditional faith healers, snake rescuers, frontline health workers on the snakebites and their management. A facility check survey was conducted using pre-tested questionnaires for different levels of the government health care facilities.

RESULTS

Most of the tribal community was aware of the commonly found snakes and their hiding places. However, there was inadequate knowledge on the identification and classification of venomous snakes. Belief in a snake god, the perception that snakes will not come out during thunderstorms, change in taste sensation, the ability of tamarind seeds or magnet to reduce the venom effect were some of the superstitions reported by the tribal community. The application of a harmful method (Tourniquet) as the first aid for snakebite was practiced by the tribal community. They preferred herbal medicines and visiting the traditional faith healers before shifting the patient to the government health facility. The knowledge on the ability to identify venomous snakebites and anti-venom was significantly higher amongst nurses and accredited social health activists (ASHAs) than auxiliary nurse midwives (ANMs) and multi-purpose workers (MPWs) (p < 0.05). None of the traditional faith healers; but nearly 60% of snake rescuers were aware of anti-venom. Fifty percent of the medical officers in Dahanu block did not have correct knowledge about the Krait bite symptoms, and renal complications due to the Russell viper bite.

CONCLUSIONS

Inappropriate perception, inadequate awareness, and knowledge about snakes and snakebites may predispose the tribal community to increased risks of venomous snakebites. Unproven and harmful methods for snakebite treatment practiced by the community and traditional faith healers could be dangerous leading to high mortality. Therefore, a multi-sectoral approach of community awareness, mapping of vulnerable populations, capacity building of health care facility, empowerment of health care workers (HCWs) could be useful for reducing the mortality and morbidity due to snakebite envenoming in India.

Genus Arisaema: A Review of Traditional Importance, Chemistry and Biological Activities

BACKGROUND

The Arisaema (Araceae) is a genus of approximately 180 perennial herbs widely distributed in the evergreen and deciduous forests. This genus (Arisaema) has been used as a medicinal agent since ancient times. Experimental investigations have shown a promising positive correlation with its folklore claim and this encourages us to report updated medicinal review (genus Arisaema) for future research.

OBJECTIVE

This review aimed to summarize the ethnobotany, folklore uses, chemistry and biological activities.

CONCLUSION

The comprehensive literature on genus Arisaema indicates the presence of terpenoids, flavonoids, and glycosphingolipids as the principal chemical constituents. Additionally, phytosterols, alkaloids, carboline derivatives and miscellaneous compounds were documented in plants of genus Arisaema. Biological investigations led to the credentials of antioxidant, anticancer, insecticidal, antimicrobial, anthelmintic and hepatoprotective activities. Following, several plant species are promising candidates for the treatment of cancer, parasitic diseases and microbial infection complications. Though, a lot of facets of this genus like phytoconstituents identification, mechanistic profile, adverse effects and clinical studies are still quite limited. Thus, this systematic review may act as a powerful tool in future studies for promoting health benefits against various health hazards.

Antihyaluronidase and Alkaline Phosphatase (ALP) Activities of Medicinal Plants to Combat Echis carinatus Venom-Induced Toxicities

Snakebite is one of the most neglected diseases of developing countries. Deaths due to snakebite envenoming are quite high in Pakistan, and many deaths are caused by Echis carinatus envenomation. Traditional use of medicinal plants against snakebites is a common practice in Pakistan due to countless benefits. The current study was performed with the objective to evaluate eighteen Pakistani medicinal plants inhibitory potential against hyaluronidase and alkaline phosphatase enzymes of Pakistani Echis carinatus venom. Hyaluronidase activity (0.2-1.6 mg/0.1 mL) and alkaline phosphatase activity (0.1-0.8 mg/0.1 mL) were measured in dose-dependent manner. Crude methanolic extracts of medicinal plants were used for in vitro investigation of their inhibitory activity against toxic enzymes. All active plants were fractioned using different solvents and were again analyzed for inhibitory activity of same enzymes. Results indicated all plants were able to neutralize hyaluronidase that Swertia chirayita (Roxb. ex Flem.) Karst., Terminalia arjuna Wight and Arn, Rubia cordifolia Thumb., and Matthiola incana (L.) R.Br. inhibited maximum hyaluronidase activity equivalent to standard reference (p > 0.5). Pakistani medicinal plants are dense with natural neutralizing metabolites and other active phytochemicals which could inhibit hyaluronidase activity of Pakistani Echis carinatus venom. Further advanced studies at molecular level could lead us to an alternative for envenoming of Pakistani Echis carinatus venom.

Anti-5'-Nucleotidases (5'-ND) and Acetylcholinesterase (AChE) Activities of Medicinal Plants to Combat Echis carinatus Venom-Induced Toxicities

Echis carinatus is one of the highly venomous snakes of Pakistan that is responsible for numerous cases of envenomation and deaths. In Pakistan, medicinal plants are commonly used traditionally for snakebite treatment because of their low cost and easy availability in comparison with antivenom. The current research is aimed at evaluating the inhibitory activity of Pakistani medicinal plants against acetylcholinesterase and 5′-nucleotidases present in Echis carinatus venom. Acetylcholinesterase and 5′-nucleotidase enzymatic assays were performed at different venom concentrations to check the activity of these enzymes. Methanolic extracts from different parts of plants were used for in vitro determination of their inhibitory activity against 5′-nucleotidases in snake venom. Active methanolic extracts were subsequently fractioned using different solvents, and these fractions were also assessed for their anti-5′-nucleotidase activity. Results of this study exhibited that Eugenia jambolana Willd. ex O. Berg, Rubia cordifolia L., Trichodesma indicum (L.) R. Br., Calotropis procera (Wild.) R. Br., Curcuma longa L., and Fagonia arabica L. were able to significantly (p > 0.5) neutralize the 5′-nucleotidase activity by 88%, 86%, 86%, 85%, 83.7%, and 83%, respectively, compared with a standard antidote (snake venom antiserum). Thus, this study indicates that these plants possess the potential to neutralize one of the toxic enzymatic components of Echis carinatus venom and hence can help to augment the future efforts of developing alternative therapy for the management of snakebites.

Care-seeking behaviour of suspected snakebite cases admitted in a medical college of West Bengal: A pathway analysis

BACKGROUND

Snakebite is a time decisive medical emergency requiring contact with health facility at the earliest. Many snakebite victims yet seek care from traditional healers (THs) or village quacks (VQs) before reaching an appropriate facility, which leads to adverse consequences. This study was conducted to assess care-seeking behaviour and pathways followed in reaching appropriate facilities among suspected snakebite cases and to identify associated factors.

METHODS

A hospital-based cross-sectional study was conducted at a medical college in West Bengal. All suspected snakebite cases admitted during a reference period of two months were studied. Study subjects and/or accompanying persons were interviewed for care-seeking behaviours and pathways followed.

RESULTS

Among the 393 study participants, most were ≤30 years of age, men, agricultural workers, of lower middle and lower socioeconomic class and only 69.5% had formal schooling. The commonest place of occurrence was the agricultural field (40.7%), and the commonest biting site was the lower extremity (77.6%). Only half of participants (55.2%) used immediate correct measures at the biting site. Incorrect practices included tourniquet application (29.5%), use of herbal preparation (7.1%), blade shaving at site (2.8%) etc. As first care-seeking points, 15% and 24.9% of cases visited THs and VQs, respectively. Pathway analysis revealed that unfavourable pathway was followed by 39.9% participants. Two unfavourable points were consulted by 3.8% of participants. The care-seeking pathway was significantly associated with religion, caste, education and socioeconomic class.

CONCLUSIONS

Findings of this study highlight the urgent need for behaviour change interventions addressing the myths and misconceptions of people regarding snakebite.

In silico and in vitro neutralization of PLA2 activity of Daboxin P by butein, mimosine and bakuchiol

Medicinal plants have always been used for snakebite treatment by traditional healers but they lack scientific evidence of action. However secondary metabolites of such plants have been explored and found to inhibit the toxic effect of venom proteins. Literature survey from 2003 to 2019 resulted in identification of 251 secondary metabolites with such properties. In silico docking studies of these metabolites with modelled structure of Daboxin P, a PLA₂ from Indian Daboia russelii revealed that butein, mimosine and bakuchiol bind to Daboxin P with high affinity. Butein interacted with the catalytic triad but mimosine and bakuchiol interacted with the Ca²⁺ binding residues of Daboxin P. In vitro validation showed that the molecules inhibited the sPLA₂ activity of Daboxin P. Interestingly, mimosine and bakuchiol could also neutralize the anti-coagulatory activity of Daboxin P. Further, it was observed that butein and mimosine could neutralize the PLA₂ activity of Indian big four venoms dose dependently. On the other hand, mimosine and bakuchiol could also neutralize the pro/anti-coagulatory effect of big four crude venom. Thus, in this study, three molecules have been identified which can neutralize the PLA₂ activity and pro/anti-coagulatory effect of Daboxin P as well as crude venom of big four.

Green synthesis of silver nanoparticles using Indian male fern (Dryopteris Cochleata), operational parameters, characterization and bioactivity on Naja naja venom neutralization

Snakebite is considered as one of the acute severe medical problems across the world. Snake venoms composed of various group of toxins, enzymes and non-toxic enzymes. Phospholipases A₂ present in Naja naja snake venom plays a significant role in lipid signalling and contributes to different inflammation in the human body. Dryopteris cochleata rhizomes have antioxidant, antimicrobial property and used to treat lesions, gonorrhoea, sores, muscular pain, rheumatic and also useful in dog and snake bites. In this study, Indian male fern D. cochleata rhizomes have been used for green synthesis of silver nanoparticles with the aim to increase the bioactivity of plant extract and to evaluate N. naja snake venom inhibition activity of prepared nanoparticles. Green synthesized nanoparticles were characterized with the help of ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray powder diffraction and atomic force microscopy. Naja naja venom inhibition activity of nanoparticles was performed using in vitro phospholipases A₂ assay and tissue damage activity. The results showed that surface plasmon resonance maxima peaks of nanoparticles were observed at 424 nm. Average particle size was around 35 nm, with a spherical shape. Neutralization results exhibited that synthesized silver nanoparticles from D. cochleata decreased percentage of tissue damage, resulting in significant inhibition of phospholipase A₂ and N. naja snake venom. Results concluded that green synthesized silver nanoparticles from D. cochleata rhizome neutralize N. naja snake venom activity.

Infrequent use of medicinal plants from India in snakebite treatment

Snakes have fascinated humankind for millennia. Snakebites are a serious medical, social, and economic problem that are experienced worldwide; however, they are most serious in tropical and subtropical countries. The reasons for this are 1) the presence of more species of the most dangerous snakes, 2) the inaccessibility of immediate medical treatment, and 3) poor health care. The goal of this study was to collect information concerning rare, less utilized, and less studied medicinal plants. More than 100 plants were found to have potential to be utilized as anti-snake venom across India. Data accumulated from a variety of literature sources revealed useful plant families, the parts of plants used, and how to utilize them. In India, there are over 520 plant species, belonging to approximately 122 families, which could be useful in the management of snakebites. This study was conducted to encourage researchers to create herbal antidotes, which will counteract snake venom. These may prove to be an inexpensive and easily assessable alternative, which would be of immense importance to society. Plants from families such as Acanthaceae, Arecaceae, Apocynaceae, Caesalpiniaceae, Asteraceae, Cucurbitaceae, Fabaceae, Euphorbiaceae, Lamiaceae, Rubiaceae, and Zingiberaceae are the most useful. In India, experts of folklore are using herbs either single or in combination with others.

Why snakebite patients in Myanmar seek traditional healers despite availability of biomedical care at hospitals? Community perspectives on reasons

BACKGROUND

Snakebite is a major public health problem in many developing countries. Farmers are particularly exposed to snakes, and due to their rural location often experience delays in accessing formal healthcare. The reasons to use traditional healers may include difficulties in accessing formal healthcare, certain beliefs about snakes and snake venom, tradition, and trust in the capacity of traditional healers. Traditional healing, however, may have serious consequences in terms of delays or added complications. There is little in-depth current information about the reasons for its continued use for snakebite. As part of a health services development project to improve health outcomes for snakebite patients, community attitudes to the use of traditional healers were explored in the Mandalay region of Myanmar.

METHODOLOGY & FINDINGS

With the objective of learning from local communities, information was generated in three communities using participatory appraisal methods with the communities, and focus group discussions with the local healthcare staff. Many snakebite victims in these communities use traditional healing. Reasons include transport difficulties, low cost for traditional healing, inadequacy of anti-snake venom in the formal healthcare sector, and traditional beliefs, as traditional healing practices are rooted in many cultural and traditional factors. The communities reported that even if access to medical care were improved, traditional healing would continue to be used.

CONCLUSION

These findings point to the need for working with traditional healers for prevention, appropriate first aid and timely access to effective treatment for snakebite.

MP-4 Contributes to Snake Venom Neutralization by Mucuna pruriens Seeds through an Indirect Antibody-mediated Mechanism

Mortality due to snakebite is a serious public health problem, and available therapeutics are known to induce debilitating side effects. Traditional medicine suggests that seeds of Mucuna pruriens can provide protection against the effects of snakebite. Our aim is to identify the protein(s) that may be important for snake venom neutralization and elucidate its mechanism of action. To this end, we have identified and purified a protein from M. pruriens, which we have named MP-4. The full-length polypeptide sequence of MP-4 was obtained through N-terminal sequencing of peptide fragments. Sequence analysis suggested that the protein may belong to the Kunitz-type protease inhibitor family and therefore may potentially neutralize the proteases present in snake venom. Using various structural and biochemical tools coupled with in vivo assays, we are able to show that MP-4 does not afford direct protection against snake venom because it is actually a poor inhibitor of serine proteases. Further experiments showed that antibodies generated against MP-4 cross-react with the whole venom and provide protection to mice against Echis carinatus snake venom. This study shows that the MP-4 contributes significantly to the snake venom neutralization activity of M. pruriens seeds through an indirect antibody-mediated mechanism.

Local and systemic toxicity of Echis carinatus venom: neutralization by Cassia auriculata L. leaf methanol extract

Viper bites cause high morbidity and mortality especially in tropical and subtropical regions, affecting a large number of the rural population in these areas. Even though anti-venoms are available, in most cases they fail to tackle viper venom-induced local manifestations that persist even after anti-venom administration. Several studies have been reported the use of plant products and approved drugs along side anti-venom therapy for efficient management of local tissue damage. In this regard, the present study focuses on the protective efficacy of Cassia auriculata L. (Leguminosae) against Echis carinatus venom (ECV) induced toxicity. C. auriculata is a traditional medicinal plant, much valued in alternative medicine for its wide usage in ayurveda, naturopathy, and herbal therapy. Further, it has been used widely by traditional healers for treatment of snake and scorpion bites in the Western Ghats of Karnataka, India. In the present study, C. auriculata leaf methanol extract (CAME) significantly inhibited enzymatic activities of ECV proteases (96 ± 1 %; P = 0.001), PLA2 (45 ± 5 %; P = 0.01) and hyaluronidases (100 %; P = 0.0003) in vitro and hemorrhage, edema and myotoxicity in vivo. Further, CAME effectively reduced the lethal potency of ECV and increased the survival time of mice by ~6 times (17 vs 3 h). These inhibitory potentials of CAME towards hydrolytic enzymes, mortal and morbid symptoms of ECV toxins clearly substantiates the use by traditional healers of C. auriculata as a folk medicinal remedy for snakebite.

Snakebite profile from a medical college in rural setting in the hills of Himachal Pradesh, India

Objective:

The objective of the following study is to assess the clinical profiles and manifestations of snakebite patients in the rural hilly setting of Shivalik and the Lesser Himalayan region of Himachal Pradesh.

Materials and Methods:

A hospital record-based retrospective descriptive study was carried out that included details on demography, clinical profile, treatment and outcome among 200 patients over a period of 2 years. The data was analyzed using Chi-square test for comparison.

Results:

142 (71%) patients were young (age group of 16-45 years) and the number of male patients was 118 (59%) and female patients were 82 (41%). All the cases recorded presented in the months of April to November. Not a single case was recorded from December to March. The most frequently bitten sites were the lower limbs particularly the feet. 86 (43%) of the patients presented without any features of envenomation. Neuroparalysis was the commonest presentation in 53 (46%) patients followed by hemotoxicity in 36 (31%) among symptomatic patients. Early morning neuroparalysis syndrome was the presentation in 26.4% patients. Allergic reactions in the form of early anaphylaxis were noted in 7% patients.

Conclusion:

Snake bite is a neglected tropical disease affecting poor villagers in rural areas. Future research focusing on understanding epidemiological determinants of snake bite is desired.