Antiplasmodial activity of atisinium chloride from the Bhutanese medicinal plant, Aconitum orochryseum

Exploring the Therapeutic Potential of Traditional Antimalarial and Antidengue Plants: A Mechanistic Perspective

Malaria, a highly perilous infectious disease, impacted approximately 230 million individuals globally in 2019. Mosquitoes, vectors of over 10% of worldwide diseases, pose a significant public health menace. The pressing need for novel antimalarial drugs arises due to the imminent threat faced by nearly 40% of the global population and the escalating resistance of parasites to current treatments. This study comprehensively addresses prevalent parasitic and viral illnesses transmitted by mosquitoes, leading to the annual symptomatic infections of 400 million individuals, placing 100 million at constant risk of contracting these diseases. Extensive investigations underscore the pivotal role of traditional plants as rich sources for pioneering pharmaceuticals. The latter half of this century witnessed the ascent of bioactive compounds within traditional medicine, laying the foundation for modern therapeutic breakthroughs. Herbal medicine, notably influential in underdeveloped or developing nations, remains an essential healthcare resource. Traditional Indian medical systems such as Ayurveda, Siddha, and Unani, with a history of successful outcomes, highlight the potential of these methodologies. Current scrutiny of Indian medicinal herbs reveals their promise as cutting-edge drug reservoirs. The propensity of plant-derived compounds to interact with biological receptors positions them as prime candidates for drug development. Yet, a comprehensive perspective is crucial. While this study underscores the promise of plant-based compounds as therapeutic agents against malaria and dengue fever, acknowledging the intricate complexities of drug development and the challenges therein are imperative. The journey from traditional remedies to contemporary medical applications is multifaceted and warrants prudent consideration. This research aspires to offer invaluable insights into the management of malaria and dengue fever. By unveiling plant-based compounds with potential antimalarial and antiviral properties, this study aims to contribute to disease control. In pursuit of this goal, a thorough understanding of the mechanistic foundations of traditional antimalarial and antidengue plants opens doors to novel therapeutic avenues.

A review on efforts for improvement in medicinally important chemical constituents inAconitum through biotechnological interventions

The genus Aconitum belongs to the family Ranunculaceae, is endowed with more than 350 species on the earth. Medicinally important aconitine type of diterpenoid alkaloids are the characteristic compounds in most of the Aconitum species. The present review endeavored the major research carried out in the field of genetic resource characterization, pharmacological properties, phytochemistry, major factors influencing quantity, biosynthetic pathways and processing methods for recovery of active ingredients, variety improvement, propagation methods, and important metabolite production through cell/organ culture of various Aconitum species. More than 450 derivatives of aconitine-type C19 and C20-diterpenoid alkaloids along with a few other non-alkaloidal compounds, such as phenylpropanoids, flavonoids, terpenoids, and fatty acids, have been identified in the genus. A few Aconitum species and their common diterpenoid alkaloid compounds are also well characterized for analgesic, inflammatory and cytotoxic properties. However, the different isolated compound needs to be validated for supporting other traditional therapeutical uses of the plant species. Aconitine alkaloids shared common biosynthesis pathway, but their diversification mechanism remains unexplored in the genus. Furthermore, the process needs to be developed on secondary metabolite recovery, mass-scale propagation methods, and agro-technologies for maintaining the quality of products. Many species are losing their existence in nature due to over-exploitation or anthropogenic factors; thus, temporal monitoring of the population status in its habitat, and suitable management programs for ascertaining conservation needs to be developed.

Antiplasmodial diterpenoid alkaloid from Aconitum heterophyllum Wall. ex Royle: Isolation, characterization, and UHPLC-DAD based quantification

ETHNOPHARMACOLOGICAL RELEVANCE

Aconitum heterophyllum Wall. ex Royle is a traditionally important medicinal plant having numerous therapeutic actions as documented in Ayurveda. This plant is traditionally known for combating worm infestation, fever, respiratory tract disease, vomiting, diarrhoea, diabetes, skin disorders, anaemia, and joint disorders. Further, it has been used alone and in combination with other plants to prepare various anti-malarial formulations. However, there is no report on the assessment of its anti-plasmodial activity, and the metabolite(s) responsible for this activity.

AIM OF THE STUDY

The main aim of this study was to conduct phytochemical investigation of A. heterophyllum roots for the preparation of extract, fractions, and isolation of pure molecules to identify active fractions/molecules responsible for the anti-plasmodial activity, and development of UHPLC-DAD based analytical method which can be used for the quantification of marker compounds in the extracts and fractions.

MATERIALS AND METHODS

Hydroalcoholic extract (1:1 v/v) and fractions (n-hexane, chloroform, ethyl acetate, n-butanol, and water) were prepared from the dried powdered roots of A. heterophyllum. Fractions were further subjected to silica gel column chromatography to isolate pure specialized secondary metabolites from this plant. All extracts, fractions, and pure molecules were evaluated against the chloroquine resistant Pf INDO and chloroquine sensitive Pf3D7 strains in culture for calculating their IC₅₀ values. UHPLC-DAD based analytical method was also developed for the first time for the quantification of marker compounds and quality assessment of this commercially important Himalayan medicinal plant.

RESULTS

Phytochemical investigation of A. heterophyllum root led to the isolation of six specialized metabolites viz. 2-O-cinnamoyl hetisine (1), atisinium (2), 4-oxabicyclo [3.2.2] nona-1(7),5,8-triene (3), atisinium cinnamate (4), aconitic acid (5), and atisinium formate (6). Compound 1 is a new hetisine type diterpenoid alkaloid, compounds 4 and 6 are new counter ionic forms observed with atisinium ion, and compound 3 is being reported for the first time from this genus. Chloroform fraction was found to be the most active with IC₅₀ (μg/mL) 1.01 (Pf INDO) and 1.32 (Pf3D7). The molecule 2-O-cinnamoyl hetisine (1), a new diterpenoid alkaloid isolated from chloroform fraction, showed promising antiplasmodial activities with IC₅₀ (μM) 1.92 (Pf INDO) and 10.8 (Pf 3D7). The activity of chloroform fraction was further validated by the developed UHPLC-DAD based method as the quantity of 2-O-cinnamoyl hetisine (1) was higher in the chloroform fraction (≅200 mg/g) than in all other fractions (<7 mg/g). Atisinium (2) and 2-O-cinnamoyl hetisine (1) were found to be the main marker compounds of this plant based on quantity and antiplasmodial activity, respectively.

CONCLUSION

This study provides the scientific rationale for the traditional use of this plant in treating malaria. Further, this study revealed that the anti-malarial potential of this plant might be due to the presence of diterpenoid alkaloids.

The diterpenoid alkaloids

The diterpenoid alkaloids are a family of extremely important natural products that have long been a research hotspot due to their myriad of intricate structures and diverse biological properties. This chapter systematically summarizes the past 11 years (2009-2019) of studies on the diterpenoid alkaloids, including the "so-called" atypical ones, covering the classification and biogenetic relationships, phytochemistry together with 444 new alkaloids covering 32 novel skeletons and the corrected structures, chemical reactions including conversion toward toxoids, synthetic studies, as well as biological activities. It should be noted that the synthetic studies, especially the total syntheses of various diterpenoid alkaloids, are for the first time reviewed in this treatise. This chapter, in combination with our four previous reviews in volumes 42, 59, 67, and 69, will present to the readers a more completed and updated profile of the diterpenoid alkaloids.

Diterpenoid alkaloids from Delphinium forrestii var. viride and their anti-inflammation activity

Six undescribed diterpenoid alkaloids including five C₁₉-diterpenoid alkaloids forrestlines A-E, and one C₂₀-diterpenoid alkaloid forrestline F, together with nine known alkaloids have been isolated from the whole herbs of Delphinium forrestii var. vride. Their structures were elucidated by spectroscopic data, and their inhibitory activities on NO production stimulated by LPS in RAW264.7 macrophage cells were determined. Then, forrestline F, with the strongest inhibitory activity (IC₅₀ of 9.57 ± 1.43 μM), was selected to study its possible anti-inflammatory mechanism. ELISA results showed that forrestline F suppressed inflammatory cytokines, including interleukin-1β (IL-1β), tumor necrosisfactor-α (TNF-α), and interleukin-6 (IL-6). Moreover, forrestline F could down-regulate LPS-induced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) by western blotting assay. It also inhibited expression of phosphorylation of MAPKs (including p-p38, p-ERK and p-JNK), and NF-κB p65, and decreased ROS accumulation by upregulating the expression of HO-1 expression via nuclear translocation of Nrf2. In conclusion, forrestline F showed anti-inflammatory effect by inhibiting NF-κB/MAPK and Nrf2/HO-1 signaling pathway. Therefore, forrestline F could be a promising molecule for the development of anti-inflammatory agents in the future.

A systematic review of pharmacological activities, toxicological mechanisms and pharmacokinetic studies on Aconitum alkaloids

The tubers and roots of Aconitum (Ranunculaceae) are widely used as heart medicine or analgesic agents for the treatment of coronary heart disease, chronic heart failure, rheumatoid arthritis and neuropathic pain since ancient times. As a type of natural products mainly extracted from Aconitum plants, Aconitum alkaloids have complex chemical structures and exert remarkable biological activity, which are mainly responsible for significant effects of Aconitum plants. The present review is to summarize the progress of the pharmacological, toxicological, and pharmacokinetic studies of Aconitum alkaloids, so as to provide evidence for better clinical application. Research data concerning pharmacological, toxicological and pharmacokinetic studies of Aconitum alkaloids were collected from different scientific databases (PubMed, CNKI, Google Scholar, Baidu Scholar, and Web of Science) using the phrase Aconitum alkaloids, as well as generic synonyms. Aconitum alkaloids are both bioactive compounds and toxic ingredients in Aconitum plants. They produce a wide range of pharmacological activities, including protecting the cardiovascular system, nervous system, and immune system and anti-cancer effects. Notably, Aconitum alkaloids also exert strong cardiac toxicity, neurotoxicity and liver toxicity, which are supported by clinical studies. Finally, pharmacokinetic studies indicated that cytochrome P450 proteins (CYPs) and efflux transporters (ETs) are closely related to the low bioavailability of Aconitum alkaloids and play an important role in their metabolism and detoxification in vivo.

Geopharmaceuticals of Himalayan Sowa Rigpa medicine: Ethnopharmacological uses, mineral diversity, chemical identification and current utilization in Bhutan

ETHNOPHARMACOLOGICAL RELEVANCE

Geological materials, such as minerals, have a long history of usage as ingredients in multicompound formulations of Himalayan Sowa Rigpa medicine - as well as in its localized form of Bhutanese traditional medicine (BTM) - for treating various disorders for over thousand years. Yet, hardly any scientific research has been done on their ethnopharmacological efficacy and chemistry.

AIM OF THE STUDY

This study documents and correlates the rarely explored ethnopharmacological and chemical identification of various minerals and their ethnomedicinal uses in BTM formulations for the first time.

MATERIAL AND METHODS

A five stage cross-disciplinary process was conducted as follows: (1) a review of classical literature of Sowa Rigpa texts (Tibetan medical texts, pharmacopoeias and formularies) that are still in use today; (2) listing of mineral ingredients according to Sowa Rigpa names, followed by identification with common English and chemical names, as well as re-translating their ethnomedical uses; (3) cross-checking the chemical names and chemical composition of identified Sowa Rigpa minerals with various geological mineral databases and mineral handbooks; (4) authentication and standardization of Sowa Rigpa names through open forum discussion with diverse BTM practitioners; (5) further confirmation of the chemical names of identified minerals by consulting different experts and pharmacognosists.

RESULTS

Our current study lists 120 minerals as described in Sowa Rigpa medical textbooks most of which we were able to chemically identify, and of which 28 are currently used in BTM herbo-mineral formulations. Out of these 28 mineral ingredients, 5 originate from precious metal and stone, 10 stem from earth, mud and rocks, 8 are salts, and 5 concern 'essences' and exudates.

CONCLUSIONS

Our study identified 120 mineral ingredients described in Sowa Rigpa medical textbooks, out of which 28 are currently used. They are crucial in formulating 108 multicompound prescription medicines in BTM presently in use for treating more than 135 biomedically defined ailments.

Diterpenes as lead molecules against neglected tropical diseases

Nowadays, neglected tropical diseases (NTDs) are reported to be present everywhere. Poor and developing areas in the world have received great attention to NTDs. Drug resistance, safety profile, and various challenges stimulate the search for alternative medications. Plant-based drugs are viewed with great interest, as they are believed to be devoid of side effects. Diterpenes, a family of essential oils, have showed attractive biological effects. A systematic review of the literature was carried out to summarize available evidences of diterpenes against NTDs. For this, databases were searched using specific search terms. Among the 2338 collected reports, a total of 181 articles were included in this review. Of them, 148 dealt with investigations using single organisms, and 33 used multiple organisms. No mechanisms of action were reported in the case of 164 reports. A total of 93.92% were related to nonclinical studies, and 4.42% and 1.66% dealt with preclinical and clinical studies, respectively. The review displays that many diterpenes are effective upon Chagas disease, chikungunya, echinococcosis, dengue, leishmaniasis, leprosy, lymphatic filariasis, malaria, schistosomiasis, and tuberculosis. Indeed, diterpenes are amazing drug candidates against NTDs. Copyright © 2016 John Wiley & Sons, Ltd.

Quality assurance of the university medical education, hospital services and traditional pharmaceutical products of the Bhutanese So-wa-rig-pa health care system

BACKGROUND

The Bhutanese So-wa-rig-pa medicine (BSM) was integrated with the allopathic (modern) health care system in 1967. Ever since the health care integration policy was implemented, the BSM has gone through many phases of quality improvement and changes including the establishment of one university-based institute, 58 hospitals and Basic Health Units (BHU)-based health care services, and one traditional medicine factory. The BSM provides primary health care services to more than 20-30 % of patients who visit hospitals and BHU on a daily basis. However, there has been no study covering the quality assurance system of BSM. Our paper addresses this information gap.

METHODS

This study was an observational ethnographic study supported by phenomenological understanding and content analysis of the data. The information was triangulated through consultation with the BSM practitioners (discussion (N = 8)) and personalized in-depth question-answer sessions using electronic protocols (N = 5). These participants comprised BSM educationists, clinical physicians, researchers, production and the quality assurance staff who were selected using convenience and purposive sampling method. The relevant So-wa-rig-pa information and literature were obtained from the government policy documents, official websites, scientific papers and the traditional medical texts. This study is enhanced by our practical observations and first-hand experience with BSM while working as the researchers at the Ministry of Health in Bhutan. In addition, the information in this paper is crosschecked and authenticated by five So-wa-rig-pa practitioners of Bhutan.

RESULTS

The study highlights the following: a) The BSM receives both the government and people's support, b) The quality assurance system have been developed by integrating the traditional empirical knowledge and modern scientific protocols, c) There exist three administrative and functional organizations responsible for providing the quality BSM health care services in Bhutan, d) Extensive standard treatment guidelines and Quality documentation system exist for BSM as required by the regulatory bodies in Bhutan. The paper also recommends appropriate future directions for BSM.

CONCLUSIONS

The BSM plays significant role in the primary health care system of the country. Consequently, the quality, safety and efficacy of BSM has been given priority by the Bhutan government. Many scientific protocols were integrated with the traditional quality approaches and further scientific studies are still required to improve its quality.

Medicinal plants of Dagala region in Bhutan: their diversity, distribution, uses and economic potential

BACKGROUND

The traditional g.so-ba-rig-pa hospitals in Bhutan uses more than 100 polyingredient medicines that are manufactured by the Menjong Sorig Pharmaceuticals (MSP). The MSP has been collecting medicinal plants from Lingzhi region for about 48 years and therefore the ecological pressure on these plants have increased. It is MSP's top priority to identify an alternative collection site to ease the problem. Therefore, this study was carried out to determine whether Dagala region could potentially be an alternative collection site for MSP.

METHODS

First the multidisciplinary research team generated a tentative plant list by reviewing a body of ancient g.so-ba-rig-pa literature, current formulations, and the MSP medicinal plants inventory documents. Second, the research team visited the study areas in Dagala region for spot identification of medicinal plants. Third, we confirmed our traditional and botanical identification by crosschecking the descriptions with the series of books on traditional texts, Flora of Bhutan, scientific papers on medicinal plants, and the plant databases.

RESULTS

We have identified 100 species of high altitude medicinal plants from Dagala region. Of these, 24 species grow abundantly, 29 species grow in moderate numbers and 47 species were scarce. More than 85 species belonged to the herbaceous life form and 51 of them are used as a whole plant. A total of 68 species grow in between 4000 and 4999 meter above sea level. These 100 medicinal plants represented 39 different families and 80 genera and the maximum number of plants belonged to the family Asteraceae. Of 60 species that are currently used for formulating medicines at MSP, 16 species have economic importance with potential for commercial collection. Out of seven areas covered by the survey, Kipchen hosted maximum number of medicinal plants (21 species).

CONCLUSIONS

Our survey identified 100 medicinal plants from Dagala region and of these, 16 species has economic potential that could benefit both MSP and Dagala communities. It is feasible to establish an alternative medicinal plants collection center in Dagala Gewog.

Diterpenoid alkaloids of Aconitum laciniatum and mitigation of inflammation by 14-O-acetylneoline in a murine model of ulcerative colitis

Aconitum laciniatum is used in Bhutanese traditional medicine for treating various chronic infections and inflammatory conditions. We carried out in-depth isolation and characterization of the phytochemicals from the root component and determined the anti-inflammatory effects of the isolated compounds against chemically-induced colitis in mice. Five diterpenoid alkaloids - pseudaconitine, 14-veratroylpseudaconine, 14-O-acetylneoline, neoline, and senbusine A - were isolated from A. laciniatum for the first time. Two of the alkaloids were tested for anti-inflammatory properties in the TNBS-induced colitis model in mice. Various parameters were measured to assess pathology including weight loss, clinical and macroscopic scores, histological structure and IFN-γ production in the gut. Of the two alkaloids tested, 14-O-acetylneoline showed significant protection against different parameters of colitic inflammation. Compared to control mice that received TNBS alone, mice treated with 14-O-acetylneoline experienced significantly less weight loss and had significantly lower clinical scores, macroscopic pathology and grades of histological inflammation. Moreover, colonic IFN-γ mRNA levels were significantly reduced in mice that received 14-O-acetylneoline compared to control mice that received TNBS alone. This alkaloid is now considered a novel anti-colitis drug lead compound.

Contributions of medicinal plants to the Gross National Happiness and Biodiscovery in Bhutan

BACKGROUND

The medicinal plants and the associated Bhutanese traditional medicine (BTM) are protected by the country's constitution and receive both government support and acceptance by the wider public. More than 1000 medicinal plants are described in the BTM but currently collects only 300 species for daily formulations of BTM. These medicinal plants have been one of the drivers of the 'Gross National Happiness (GNH)' and biodiscovery projects in Bhutan. However, no review covering the systematic evaluations of the contributions of medicinal plants and the BTM to the GNH and biodiscovery exist till date.

METHODS

This paper, therefore addresses this information gap. It is based on the review of the existing traditional and scientific literature, government websites and policy documents. The descriptions and discussions of the paper is straightened, authenticated and enhanced by the data collected through the informal discussions with the BTM practitioners and also through the authors' many years of practical observations of the impact of the medicinal plants programs and the BTM practices in Bhutan.

RESULTS

This paper found the following: a) the medicinal plants generates income to the farmers elevating their living standard and the economic status, b) it serves as the bulk ingredients of the BTM facilitating the provision of free traditional health care services to the patients, c) helps the conservation of medicinal plants and their pristine environment through recognition of their spiritual, social and economic values, d) preserves the rich BTM cultural heritage, and e) guides the biodiscovery projects based on their ethnobotanical information. The paper also identified the challenges and research gaps, and recommends appropriate strategies that can help secure the sustainable future of the medicinal plants, the BTM and the biodiscovery projects.

CONCLUSIONS

The medicinal plants play significant role in the country's biodiscovery projects and the internationally renowned development policy of 'Gross National Happiness'.

An assessment of the Bhutanese traditional medicine for its ethnopharmacology, ethnobotany and ethnoquality: Textual understanding and the current practices

ETHNOPHARMACOLOGICAL RELEVANCE

: This study involves the assessment of the Bhutanese traditional medicine (BTM) which was integrated with the mainstream biomedicine in 1967 to provide primary health care services in the country. It caters to 20-30% of the daily out-patients within 49 traditional medicine units attached to 20 district modern hospitals and 29 Basic Health Units in the country.

AIM OF THE STUDY

: This study presents the ethnopharmacological, ethnobotanical and the ethnoquality concepts in relation to mainstream Tibetan medicine and describes the current practices of BTM.

MATERIALS AND METHODS

: Experienced BTM practitioners (Drung-tshos and Smen-pas) were selected using a convenience sampling method and were interviewed using an open questionnaire followed by informal discussions. The corpus of BTM, Tibetan and scientific literature was obtained and the information on ethnopharmacological, ethnoquality and ethnobotanical concepts and current practices of BTM was extracted.

RESULTS

: This study found that the BTM shares many similarities in terms of materia medica, pharmacopoeia and the principles and concepts of ethnopharmacology and ethnobotany with its mainstream Tibetan medicine. However, the resourceful Bhutanese Drung-tshos and Smen-pas have adapted this medical system based on the local language, culture, disease trend, health care needs and their familiarity with the locally available medicinal ingredients making it particular to the country. A number of notable distinctions observed in the current practices include a code of classification of diseases (only 79 of 404 types of disorders recognized), formulations (currently used only 103 of thousands formulation types), usage of medicinal plants (only 229 species of thousands described) and selected treatment procedures (golden needle and water therapy). This BTM was found to cater to 20-30% of daily out-patients visiting 49 modern hospitals and basic health units in the country.

CONCLUSIONS

: The BTM has been evolved from the Tibetan medicine. While the pharmacopoeia, ethnopharmacology, ethnobotany and the ethnoquality aspects shares commonalities with the mainstream Tibetan medicine, there are some practices unique to BTM. Such uniqueness observed in the current practices of BTM include formulations, medicinal plants collection and usage, and the treatment procedures including golden needle and water therapy. This could be a promising source of information for the rediscovery of useful remedies, the development of modern phytotherapeutics and the establishment of efficient quality control measures.

Antiplasmodial Natural Products

Malaria is a human infectious disease that is caused by four species of Plasmodium. It is responsible for more than 1 million deaths per year. Natural products contain a great variety of chemical structures and have been screened for antiplasmodial activity as potential sources of new antimalarial drugs. This review highlights studies on natural products with antimalarial and antiplasmodial activity reported in the literature from January 2009 to November 2010. A total of 360 antiplasmodial natural products comprised of terpenes, including iridoids, sesquiterpenes, diterpenes, terpenoid benzoquinones, steroids, quassinoids, limonoids, curcubitacins, and lanostanes; flavonoids; alkaloids; peptides; phenylalkanoids; xanthones; naphthopyrones; polyketides, including halenaquinones, peroxides, polyacetylenes, and resorcylic acids; depsidones; benzophenones; macrolides; and miscellaneous compounds, including halogenated compounds and chromenes are listed in this review.