Elicitation of Submerged Adventitious Root Cultures of Stevia rebaudiana with Cuscuta reflexa for Production of Biomass and Secondary Metabolites

Stevia rebaudiana is an important medicinal plant that belongs to the Asteraceae family. The leaves of Stevia rebaudiana are a rich source of many health-promoting agents such as polyphenols, flavonoids, and steviol glycoside, which play a key role in controlling obesity and diabetes. New strategies such as the elicitation of culture media are needed to enhance the productivity of active components. Herein, the Cuscuta reflexa extracts were exploited as elicitors to enhance the productivity of active components. Cuscuta reflexa is one of the parasitic plants that has the ability to elongate very fast and cover the host plant. Consequently, it may be possible that the addition of Cuscuta reflexa extracts to adventitious root cultures (ADR) of Stevia rebaudiana may elongate the root more than control cultures to produce higher quantities of the desired secondary metabolites. Therefore, the main objective of the current study was to investigate the effect of Cuscuta reflexa extract as a biotic elicitor on the biomass accumulation and production of antioxidant secondary metabolite in submerged adventitious root cultures of Stevia rebaudiana. Ten different concentrations of Cuscuta reflexa were added to liquid media containing 0.5 mg/L naphthalene acetic acid (NAA). The growth kinetics of adventitious roots was investigated for a period of 49 days with an interval of 7 days. The maximum biomass accumulation (7.83 g/3 flasks) was observed on medium containing 10 mg/L extract of Cuscuta reflexa on day 49. As the concentration of extract increases in the culture media, the biomass gradually decreases after 49 days of inoculation. In this study, the higher total phenolics content (0.31 mg GAE/g-DW), total flavonoids content (0.22 mg QE/g-DW), and antioxidant activity (85.54%) were observed in 100 mg/L treated cultures. The higher concentration (100 mg/L) of Cuscuta reflexa extract considerably increased the total phenolics content (TPC), total phenolics production (TPP), total flavonoids content (TFC), total flavonoids production (TFP), total polyphenolics content (TPPC), and total polyphenolics production (TPPP). It was concluded that the extract of Cuscuta reflexa moderately improved biomass accumulation but enhanced the synthesis of phenolics, flavonoids, and antioxidant activities. Here, biomass’s independent production of secondary metabolites was observed with the addition of extract. The present study will be helpful to scale up adventitious roots culture into a bioreactor for the production of secondary metabolites rather than biomass accumulation in medicinally important Stevia rebaudiana.

Quantitative Ethnobotanical Analysis of Medicinal Plants of High-Temperature Areas of Southern Punjab, Pakistan

Lack of proper infrastructure and the poor economic conditions of rural communities make them dependent on herbal medicines. Thus, there is a need to obtain and conserve the historic and traditional knowledge about the medicinal importance of different plants found in different areas of the world. In this regard, a field study was conducted to document the medicinal importance of local plants commonly used by the inhabitants of very old historic villages in Southern Punjab, Pakistan. In total, 58 plant species were explored, which belonged to 28 taxonomic families, as informed by 200 experienced respondents in the study area. The vernacular name, voucher number, plant parts used, and medicinal values were also documented for each species. Among the documented species, Poaceae remained the most predominant family, followed by Solanaceae and Asteraceae. The local communities were dependent on medicinal plants for daily curing of several ailments, including asthma, common cold, sore throat, fever, cardiovascular diseases, and digestive disorders. Among the reported species, leaves and the whole plant remained the most commonly utilized plant parts, while extracts (38.8%) and pastes (23.9%) were the most popular modes of utilization. Based on the ICF value, the highest value was accounted for wound healing (0.87), followed by skincare, nails, hair, and teeth disorders (0.85). The highest RFC value was represented by Acacia nilotica and Triticum aestivum (0.95 each), followed by Azadirachta indica (0.91). The highest UV was represented by Conyza canadensis and Cuscuta reflexa (0.58 each), followed by Xanthium strumarium (0.37). As far as FL was concerned, the highest value was recorded in the case of Azadirachta indica (93.4%) for blood purification and Acacia nilotica (91.1%) for sexual disorders. In conclusion, the local inhabitants primarily focus on medicinal plants for the treatment of different diseases in the very old historic villages of Southern Punjab, Pakistan. Moreover, there were various plants in the study area that have great ethnobotanical potential to treat various diseases, as revealed through different indices.

ANTI-INFLAMMATORY PROPERTIES OF UNEXPLORED PLANTS – CUSCUTA REFLEXA AND COCCULUS HIRSUTUS – AN EXPERIMENTAL STUDY

Objective: The study aimed to document the rarely explored plants, namely, Cuscuta reflexa (CRA) and Cocculus hirsutus (CHP) used by the ethnic people of a specific region. The anti-inflammatory (AI) property of kwath of CRA (KCRA), kwath of CHP (KCHP), and their blend (kwath blend [KB]) was also assessed. Methods: The KCRA and KCHP were prepared following standard Ayurvedic procedures. The AI property was determined by carrageenan-induced paw edema at doses; 250, 125, and 62.5 mg/kg. The KB (500 mg/kg) was prepared using equal parts of KCRA and KCHP in view of the potential AI property as compared to the individual plants. Ibuprofen (100 mg/kg) was used as the standard AI drug standard drug (SD). Results: The carrageenan-induced paw inflammation was highest and doubled at 3 h. The oral administration of SD (100 mg/kg) produced a high reduction of edema (78.47%) at 3 h. Both KCRA and KCHP had reduced edema and were equally potent (EC50; 139.8 and 147.3 mg/kg, respectively) at the early phase. However, the efficacy of KCRA was greater than KCHP at the second phase of inflammation (EC50=313.6 and 2760 mg/kg, respectively). KCRA was efficacious and potent as an AI agent. Unlike SD, KB had effectively inhibited paw edema from the 6th h onward. The AI activity of KB was superior compared to individual plant groups. Conclusions: The study demonstrated that the traditional formulation – kwath of rarely explored plants, namely, CRA, CHP, and KB has AI property and can be explored to develop them as AI agents.

Physiological and ecological warnings that dodders pose an exigent threat to farmlands in Eastern Africa

Invasive holoparasitic plants of the genus Cuscuta (dodder) threaten African ecosystems due to their rapid spread and attack on various host plant species. Most Cuscuta species cannot photosynthesize and hence rely on host plants for nourishment. After attachment through a peg-like organ called a haustorium, the parasites deprive hosts of water and nutrients, which negatively affects host growth and development. Despite their rapid spread in Africa, dodders have attracted limited research attention, although data on their taxonomy, host range, and epidemiology are critical for their management. Here, we combine taxonomy and phylogenetics to reveal the presence of field dodder (Cuscuta campestris) and Cuscuta kilimanjari (both either naturalized or endemic to East Africa), in addition to the introduction of the giant dodder (Cuscuta reflexa), a south Asian species, in continental Africa. These parasites have a wide host range, parasitizing species across 13 angiosperm orders. We evaluated the possibility of C. reflexa to expand this host range to tea (Camelia sinensis), coffee (Coffea arabica), and mango (Mangifera indica), crops of economic importance to Africa, for which haustorial formation and vascular-bundle connections in all three crops revealed successful parasitism. However, only mango mounted a successful post-attachment resistance response. Furthermore, species distribution models predicted high habitat suitability for Cuscuta spp. across major tea- and coffee-growing regions of Eastern Africa, suggesting an imminent risk to these crops. Our findings provide relevant insights into a poorly understood threat to biodiversity and economic wellbeing in Eastern Africa, and provide critical information to guide development of management strategies to avert Cuscuta spp. spread.