Biological activity, phytochemistry and traditional uses of genus Lobelia (Campanulaceae): A systematic review

A Plant Model of α-Synucleinopathy: Expression of α-Synuclein A53T Variant in Hairy Root Cultures Leads to Proteostatic Stress and Dysregulation of Iron Metabolism

Synucleinopathies, typified by Parkinson's disease (PD), entail the accumulation of α-synuclein (αSyn) aggregates in nerve cells. Various αSyn mutants, including the αSyn A53T variant linked to early-onset PD, increase the propensity for αSyn aggregate formation. In addition to disrupting protein homeostasis and inducing proteostatic stress, the aggregation of αSyn in PD is associated with an imbalance in iron metabolism, which increases the generation of reactive oxygen species and causes oxidative stress. This study explored the impact of αSyn A53T expression in transgenic hairy roots of four medicinal plants (Lobelia cardinalis, Artemisia annua, Salvia miltiorrhiza, and Polygonum multiflorum). In all tested plants, αSyn A53T expression triggered proteotoxic stress and perturbed iron homeostasis, mirroring the molecular profile observed in human and animal nerve cells. In addition to the common eukaryotic defense mechanisms against proteostatic and oxidative stresses, a plant stress response generally includes the biosynthesis of a diverse set of protective secondary metabolites. Therefore, the hairy root cultures expressing αSyn A53T offer a platform for identifying secondary metabolites that can ameliorate the effects of αSyn, thereby aiding in the development of possible PD treatments and/or treatments of synucleinopathies.

LC-ESI-MS/MS-Based Comparative Metabolomic Study, Antioxidant and Antidiabetic Activities of Three Lobelia Species: Molecular Modeling and ADMET Study

The hydroethanol (70%) extracts of three Lobelia species (L. nicotianifolia, L. sessilifolia, and L. chinensis) were analyzed using LC-ESI-MS/MS. Forty-five metabolites were identified, including different flavonoids, coumarin, polyacetylenes, and alkaloids, which were the most abundant class. By applying Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) based on LC-ESI-MS/MS analysis, the three species were completely segregated from each other. In addition, the three Lobelia extracts were tested for their antioxidant activities using a DPPH assay and as antidiabetic agents against α-glycosidase and α-amylase enzymes. L. chinensis extract demonstrated significant antioxidant activity with an IC50 value of 1.111 mg/mL, while L. nicotianifolia showed mild suppressing activity on the α-glycosidase activity with an IC50 value of 270.8 μg/mL. A molecular simulation study was performed on the main compounds to predict their potential antidiabetic activity and pharmacokinetic properties. The molecular docking results confirmed the α-glycosidase inhibitory activity of the tested compounds, as seen in their binding mode to the key amino acid residues at the binding site compared to that of the standard drug acarbose. Furthermore, the predictive ADMET results revealed good pharmacokinetic properties of almost all of the tested compounds. The biological evaluation results demonstrated the promising activity of the tested compounds, aligned with the in silico results.

Poisonous Piperidine Plants and the Biodiversity of Norditerpenoid Alkaloids for Leads in Drug Discovery: Experimental Aspects

There are famous examples of simple (e.g., hemlock, Conium maculatum L.) and complex (e.g., opium poppy, Papaver somniferum L., Papaveraceae) piperidine-alkaloid-containing plants. Many of these are highly poisonous, whilst pepper is well-known gastronomically, and several substituted piperidine alkaloids are therapeutically beneficial as a function of dose and mode of action. This review covers the taxonomy of the genera Aconitum, Delphinium, and the controversial Consolida. As part of studying the biodiversity of norditerpenoid alkaloids (NDAS), the majority of which possess an N-ethyl group, we also quantified the fragment occurrence count in the SciFinder database for NDA skeletons. The wide range of NDA biodiversity is also captured in a review of over 100 recently reported isolated alkaloids. Ring A substitution at position 1 is important to determine the NDA skeleton conformation. In this overview of naturally occurring highly oxygenated NDAs from traditional Aconitum and Delphinium plants, consideration is given to functional effect and to real functional evidence. Their high potential biological activity makes them useful candidate molecules for further investigation as lead compounds in the development of selective drugs.

Identification of lobetyolin as a major antimalarial constituent of the roots of Lobelia giberroa Hemsl

Lobelia giberroa Hemsl. is an endogenous Ethiopian medicinal plant with a long history of use in the treatment of malaria, bacterial and fungal diseases, and cancer. Here, we present the in vivo bioassay-guided fractionation of the 80% methanol extract of L. giberroa roots, which led to the isolation of lobetyolin. L. giberroa roots were extracted with 80% methanol, and the dried 80% methanol extract was fractionated with hexane, ethyl acetate, methanol, and water. Acute oral toxicity study was conducted according to the Organisation for Economic Co-operation and Development Guideline 425 by using female Swiss albino mice. Antimalarial activity was assessed in Plasmodium berghei-infected Swiss albino mice. Through in vivo bioassay-guided fractionation processes lobetyolin, a C14-polyacetylene glucoside, was isolated from the methanol fraction by silica gel column chromatography as the main active ingredient from the plant. The chemical structure of lobetyolin was elucidated by interpretation of spectroscopic data (¹HNMR, ¹³CNMR, IR. MS) including two dimensional NMR. The plant extract was considered safe for administration up to 2000 mg/kg. In the four-day suppressive test, the 80% methanol extract (400 mg/kg), methanol fraction (400 mg/kg), and lobetyolin (100 mg/kg) exhibited antimalarial activity, with chemosuppression values of 73.05, 64.37, and 68.21%, respectively. Compared to the negative control, which had a mean survival time of 7 days, the lobetyolin (100 mg/kg) and methanol fraction (400 mg/kg) treated groups had mean survival times of 18 and 19 days, respectively. The current study supports the traditional use of the plant for the treatment of malaria. The structural differences between lobetyolin and existing antimalarials, as well as its previously unknown antimalarial activity, make it of interest as an early lead compound for further chemical optimization.

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Multi-drug resistant malaria parasites urge the discovery of newer drugs.

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Lobelia giberroa is an indigenous traditional antimalarial plant of Ethiopia.

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In vivo antimalarial-activity-guided fractionation led to the isolation of lobetyolin.

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Lobetyolin exhibits a promising antimalarial activity with an ED₅₀ of 36.8 mg/kg.

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Lobetyolin is a potential lead compound to develop a new class of antimalarial drugs.

Anticancer Properties of Lobetyolin, an Essential Component of Radix Codonopsis (Dangshen)

Lobetyolin (LBT) is a polyacetylene glycoside found in diverse medicinal plants but mainly isolated from the roots of Codonopsis pilosula, known as Radix Codonopsis or Dangshen. Twelve traditional Chinese medicinal preparations containing Radix Codonopsis were identified; they are generally used to tonify spleen and lung Qi and occasionally to treat cancer. Here we have reviewed the anticancer properties of Codonopsis extracts, LBT and structural analogs. Lobetyolin and lobetyolinin are the mono- and bis-glucosylated forms of the polyacetylenic compound lobetyol. Lobetyol and LBT have shown activities against several types of cancer (notably gastric cancer) and we examined the molecular basis of their activity. A down-regulation of glutamine metabolism by LBT has been evidenced, contributing to drug-induced apoptosis and tumor growth inhibition. LBT markedly reduces both mRNA and protein expression of the amino acid transporter Alanine-Serine-Cysteine Transporter 2 (ASCT2). Other potential targets are proposed here, based on the structural analogy with other anticancer compounds. LBT and related polyacetylene glycosides should be further considered as potential anticancer agents, but more work is needed to evaluate their efficacy, toxicity, and risk-benefit ratio.

Beyond Alkaloids: Novel Bioactive Natural Products From Lobelia Species

In this work, we reviewed the progress in the phytochemical and biological investigations of bioactive components derived from medicinally valuable Lobelia species. In the last 60 years, Lobelia has garnered significant attention from the phytochemist from around the world, majorly due to the discovery of bioactive piperidine alkaloids (e.g., lobinaline and lobeline) in the early 1950s. Later, lobeline underwent clinical trials for several indications including the treatment of attention deficit hyperactivity disorder and a multicenter phase three trial for smoking cessation. Subsequently, several other alkaloids derived from different species of Lobelia were also investigated for their pharmacological characteristics. However, in the last few years, the research focus has started shifting to the characterization of the other novel chemical classes. The major shift has been noticed due to the structurally similar alkaloid components, which essentially share similar pharmacological, physicochemical, and toxicological profiles. In this review, we present an up-to-date overview of their progress with special attention to understanding the molecular mechanisms of the novel bioactive components.

Rhizoplane and Rhizosphere Fungal Communities of Geographically Isolated Korean Bellflower (Campanula takesimana Nakai)

Simple Summary

The current study reports fungal diversities in the rhizoplane (RP) and rhizosphere (RS) samples of the geographically isolated Korean bellflower (Campanulatakesimana) obtained from its original habitats of the eastern coast of the Korean Peninsula for the first time. The identification of specific taxa in each site may provide a better understanding of the interaction between the soil fungi and Korean bellflower.

Abstract

Fungal communities in the rhizoplane (RP) and rhizosphere (RS) of geographically isolated C. takesimana habitats in different environments such as oceanic (Seodo, the Dokdo Islands), coastline (Sadong, Ulleungdo Island), and inland (Taeha, Ulleungdo Island) regions were analyzed by MiSeq sequencing. In total, 1279 operational taxonomic units (OTUs) were obtained and they were further classified into 185 genera belonging to five phyla. The total number of fungal taxa in the RP samples was lower than those in the RS samples in all the sampled locations, providing an indication of the existence of a certain level of the selective pressures from the host plant. The richness of the RP in the Dokdo Islands was higher than that of Ulleungdo Island, but the richness of the RS in the Dokdo Islands was lower than that of Ulleungdo Island. These results suggest evidence for strong effects of a harsh geo-climate on the RP and RS fungal diversities in the Dokdo Islands. Additionally, a total of 82 fungal genera were identified in all three RP samples and 63 genera (77%) were uniquely found in each of the geographical regions and 43 genera (52.4%) showed high dependency on the C. takesimana vegetation. It was found that the genus Mortierella was the most dominant taxon in all the samples. The geo-ecological isolation of the Korean bellflower may have caused unique formation of the RP and RS fungal communities in the natural habitats.

Efficacy of Lobelia alsinoides Lam ethanolic extract on a third-degree burn: An experimental study on rats

This is the first study to evaluate the topical application of Lobelia alsinoides Lam (LT) ethanolic extract on burns in rats. A deep third-degree burn wound was inflicted in adult male Wistar rats and the burns were dressed daily with a topical ointment formulation (Patent filed) comprising of Lobelia alsinoides Lam (5% and 10% w/w). The wound had noteworthy contraction and quicker eschar removal in 10% w/w LT-treated groups followed by 5% w/w treated groups on comparing with the commonly prescribed ointment (Silverex^TM containing 1% w/w Silver sulfadiazine). Histopathological analysis showed that ointment containing 10% w/w LT ethanolic extract significantly increased fibroblast growth, which plays a major role in anatomic integrity, collagen synthesis, and accelerated the rate of the healing process. This study shows that the ethanolic extract of Lobelia alsinoides Lam, a previously pharmacologically unreported traditional medicinal plant, possesses wound contraction and eschar removal properties on burn wounds.