Dominant Alkaloid Research Articles

Dynamics of alkaloid accumulation in Narcissus cv.Hawera: a source of Sceletium-type alkaloids.

The Sceletium-type alkaloids, known for their anxiolytic and antidepressant activities, have been recently found to be biosynthesized in Narcissus cv. Hawera, which is largely used as an ornamental plant. An alkaloid fraction enriched with Sceletium-type alkaloids from the plant has shown promising antidepressant and anxiolytic activities. In the present study, qualitative and quantitative analyses of the alkaloids in the plant organs were performed during one vegetation season by GC-MS. The alkaloid pattern and total alkaloid content was found to depend strongly on the stage of development and plant organ. The alkaloid content of bulbs was found to be highest during the dormancy period and lowest in sprouting bulbs. The leaves showed the highest alkaloid content during the intensive vegetative growth andlowest during flowering. In total, 13 alkaloids were detected in the methanol extracts of Narcissus cv. Hawera, six Sceletium-type and seven typical Amaryllidaceae alkaloids. Major alkaloids in the alkaloid pattern were lycorine, 6-epi-mesembrenol, mesembrenone, sanguinine, and galanthamine. The leaves of flowering plants were found to have the highest amount of 6-epi-mesembrenol. Mesembrenone was found to be dominant alkaloid in the leaves of sprouting bulbs and in the flowers. Considering the biomass of the plant, the dormant bulbs are the best source of alkaloid fractions enriched with 6-epi-mesembrenol. Theflowers and the young leaves can be used for preparation of alkaloid fractions enriched with mesembrenone. Theresults indicates that Narcissus cv. Hawera is an emerging source of valuable bioactive compounds and its utilization can be extended as a medicinal plant.

Current Status and De Novo Synthesis of Anti-Tumor Alkaloids in Nicotiana

Alkaloids are the most diversified nitrogen-containing secondary metabolites, having antioxidant and antimicrobial properties, and are extensively used in pharmaceuticals to treat different types of cancer. Nicotiana serves as a reservoir of anti-cancer alkaloids and is also used as a model plant for the de novo synthesis of various anti-cancer molecules through genetic engineering. Up to 4% of the total dry weight of Nicotiana was found to be composed of alkaloids, where nicotine, nornicotine, anatabine, and anabasine are reported as the dominant alkaloids. Additionally, among the alkaloids present in Nicotiana, β-carboline (Harmane and Norharmane) and Kynurenines are found to show anti-tumor effects, especially in the cases of colon and breast cancers. Creating new or shunting of existing biosynthesis pathways in different species of Nicotiana resulted in de novo or increased synthesis of different anti-tumor molecules or their derivatives or precursors including Taxadiane (~22.5 µg/g), Artemisinin (~120 μg/g), Parthenolide (~2.05 ng/g), Costunolide (~60 ng/g), Etoposide (~1 mg/g), Crocin (~400 µg/g), Catharanthine (~60 ng/g), Tabersonine (~10 ng/g), Strictosidine (~0.23 mg/g), etc. Enriching the precursor pool, especially Dimethylallyl Diphosphate (DMAPP), down-regulating other bi-product pathways, compartmentalization or metabolic shunting, or organelle-specific reconstitution of the precursor pool, might trigger the enhanced accumulation of the targeted anti-cancer alkaloid in Nicotiana.

Phenolic Compounds and Pyrrolizidine Alkaloids of Two North Bluebells: Mertensia stylosa and Mertensia serrulata

Two North bluebells, Mertonian stylosa and M. serrulata, are plants used in the traditional medicine of the Buryats as wound healing and antitumor remedies. Both mertensias have been used by local healers as substitutes for the rare Tibetan raw material Cynoglossum amabile. The lack of information on the chemical composition of M. stylosa and M. serrulata herbs has prompted the study of metabolites, in particular phenolic compounds and alkaloids, as components with high biological activity. In this study, the application of liquid chromatography–mass spectrometry for the metabolite profiling of both Mertensia species resulted in the identification of 30 compounds, including hydroxycinnamates, flavonoids, and pyrrolizidine alkaloids. In particular, lycopsamine N-oxide was the dominant alkaloid in M. stylosa (5.27 mg/g) and M. serrulata (2.14 mg/g) herbs, 5-O-caffeoylquinic acid (43.41 mg/g) and rutin (42.40 mg/g) prevailed among the phenolic compounds in M. stylosa herb, while rutin (25.72 mg/g) was the dominant compound of the M. serrulata herb. The investigated extracts of M. stylosa and M. serrulata herb revealed good scavenging capacity against DPPH•, ABTS•+, and DMPD•+ radicals. To our knowledge, this is the first study of M. stylosa and M. serrulata alkaloids and phenolic compounds and antioxidativity.

STUDY OF THE CYTOTOXIC ACTIVITY OF ALKALOID- CONTAINING FRACTIONS ISOLATED FROM CERTAIN PLANT SPECIES GROWING AND INTRODUCED IN GEORGIA

The objects of the study were Ephedra procera Fisch (Fam. Ephedraceae), Taxus baccata L. (Fam. Taxaceae) and Mahonia aquifolium (Pursh) Nutt (Fam. Berberidaceae) growing or introduced in Georgia. Biologically active alkaloid-containing substances were obtained by liquid-liquid extraction. In all studied species, the dominant alkaloids belong to the acyclic, diterpene and isoquinoline groups of alkaloids, respectively. In vitro cytotoxic activity was evaluated on A-549 (lung carcinoma cell lines), DLD-1 (colon adenocarcinoma cells) and WS-1 (human fibroblast normal cell lines). The sums of alkaloids obtained from Ephedra Procera showed selective cytotoxic activity against A-549 and DLD-1. An alkaloid enriched fraction isolated from Taxus baccata L. demonstrated significant specific cytotoxic activity against A-549 and DLD-1 cell lines. The sums obtained from Mahonia aquifolium exhibited pronounced activity against all cell lines - A-549, DLD-1 and WS-1 according to the Resazurine and Hoechst models.

Screening the Synergistic Components of Acetylcholinesterase Inhibition from Phellodendron Bark Based on Fingerprint-Activity Relationship Modeling

Objective: Phellodendron chinense (PC) bark and Phellodendron amurense (PA) bark are two herbal medicines recorded in the Chinese Pharmacopoeia (2020 edition) that are easily mistaken for one another. In this study, the chemical constituents of PC and PA were compared using chromatographic fingerprints, and the potential synergistic acetylcholinesterase (AChE) inhibitor components were screened based on the correlation of fingerprint activity. Materials and Methods: Chromatographic fingerprints based on high-performance liquid chromatography were developed for the analysis and comparison of chemical compounds in PC and PA samples. The AChE inhibitory activity of PC and PA was determined using the Ellman method. Subsequently, the contribution of the characterized alkaloids in PC and PA to the overall AChE inhibition was modeled using partial least squares regression (PLSR). Results: The total alkaloid content in PC was higher than that in PA, which causes PC to have stronger anti-AChE activity. Overall, 13 and 20 common peaks were identified in the PC and PA samples, respectively. Among them, berberine (BER) was the dominant alkaloid in PC, which covered more than 65% of the total peak area in PC, but only approximately 25% of that in PA, indicating that the chemical composition is different between PC and PA. The spectrum–effect analysis based on PLSR and the correlation analysis showed that the BER-palmatine (PAL) and BER-jatrorrhizine (JAT) pairs have a synergistic inhibitory effect on AChE activity. Conclusions: A high-performance chromatographic fingerprint was established to distinguish PC and PA. The efficacy-associated markers were screened, including the pairs of BER-PAL and BER-JAT with anti-AChE activity, and the findings may assist with the quality control of PA and PC.

MICROSTRUCTURAL FEATURES OF THE VEGETATIVE ORGANS OF DELPHIUM FLEXUOSUM BIEB. COMMON IN GEORGIA

The genus Delphinium L. is rich in diterpene alkaloids, which exhibit a pronounced curare-like, anti-tumor, anti-inflammatory, analgesic, antidote and insecticidal action. The content of diterpene alkaloids in the aboveground and unde-ground vegetative organs of Delphinium flexuosum Bieb., a promising medicinal plant of the flora of Georgia, and diagnostic features of the internal structure were studied in order to determine the identity of the experimental raw material.GC/MS analysis revealed that the dominant alkaloid obtained from the vegetative organs of the plant is the pharmacologically active methyllicaconitine.  Other alkaloids have been identified as anthranoillocytonine, delcosine, lycotonine. As well, the underground organs contain also zongorine, delectine and norzongoramine. A set of diagnostic features of the internal structure of D. flexuosum was determined using the methods adopted in microtechnics. The leaf of D. flexuosum is bifacial, hypostomatic and has dorsoventral structure. It is very rarely covered with long conical trichomes, the underlying cells of the lower and upper epidermis of the leaf are non-wrinkled and curved. The differential stomatal apparatus in leaf-covering tissue is anomocytic.  Stomata are lenticular, and structure of the stomata is chaotic, in terms of the reciprocal location of the locking cells. The leaf pulp is differentiated into open, reverse-collateral conductive cones. The aboveground organs of D. flexuosum are characterized by an orderly aligned structural elements of the epidermal tissue, with linear and straight-walled stem cells and orderly arranged anomocytic stomata. Collenchymal and fibrous cells of the mechanical type and open-collateral type conducting cones with a thickening of the spiral and reticular membrane are actively reflected in the organs of the plant axis. The conductive tissue of the root system of D. flexuosum contains a number of polar rays of the wood with differentiated stepwise, spiral and ring-shaped tracheal elements.

Chemical composition and anti-inflammatory activity of water extract from black cocoa tea (Camellia ptilophylla)

Cocoa tea (Camellia ptilophylla) is a non-conventional tea variety with low caffeine and high gallocatechin gallate (GCG). The anti-inflammatory activity of black cocoa tea and its underlying mechanisms remain virtually unknown. In this study, the chemical composition and anti-inflammatory activity of water extracts from black cocoa tea (BCWE) and Yunnan Daye tea (BYWE) were compared. Results showed that the dominant alkaloid in BCWE and BYWE were theobromine and caffeine, respectively. The contents of gallic acid, total catechins, and total polyphenols in BCWE were significantly higher than those in BYWE. For tea pigments, BYWE contained a little more total theaflavins and theabrownins than BCWE, while no significant difference was observed in thearubigins. Interestingly, a novel theaflavin synthesized from GCG and catechin was found in BCWE. In lipopolysaccharide-induced RAW264.7 cells, both BCWE and BYWE could inhibit the production of nitric oxide and prostaglandin E2 by down-regulating the expression levels of inducible nitric oxide synthase and cyclooxygenase-2. They also markedly reduced the release of tumor necrosis factor-α and interleukin-6 at a high dose. Additionally, BCWE exhibited stronger anti-inflammatory activity than BYWE. Finally, BCWE exerted anti-inflammatory effect by inhibiting the activation of mitogen-activated protein kinases, phosphatidylinositol-3-kinase/protein kinase B, and nuclear factor-kappa B signaling pathways. These findings suggest that black cocoa tea can be developed into a promising functional beverage with anti-inflammatory property.

Improving galegine production in transformed hairy roots of Galega officinalis L. via elicitation

Galega officinalis L. is an herbaceous legume used to treat symptoms associated with hyperglycemia or diabetes mellitus because of its dominant alkaloid, galegine. In this study, we induced hairy roots in this plant using Rhizobium rhizogenes strain A4, and investigated the effect of type, concentration, and duration of elicitor application on galegine content and some phytochemical characteristics in the hairy roots. Hence, the best growing hairy root line in terms of growth rate was selected and subcultured for treatment with elicitors. Then, at the end of the log phase of growth, chitosan (100, 200, and 400 mg/L), salicylic acid (100, 200, and 300 mM), and ultrasound (1, 2, and 4 min) were applied to hairy roots culture medium. High-performance liquid chromatography (HPLC) showed that the content of galegine was significantly increased after elicitation compared with the control. Thus, the highest content of galegine (14.55 mg/g FW) was obtained 2 days after elicitation when ultrasonic waves were applied to the hairy root culture medium for 4 min. Also, elicitation resulted in a significant increase in the content of total phenol, flavonoid, H2O2 and MDA compared with the control. So that the highest total flavonoid content was obtained in hairy roots that were treated with ultrasonic waves for 4 min and harvested 2 days after elicitation; while, application of 400 mg/L chitosan for 4 days resulted in the highest total phenol (16.84 mg/g FW).Graphical

Abrine Elicits Liver Carcinoma Immunity and Enhances Antitumor Efficacy of Immune Checkpoint Blockade by Modulating PD-L1 Signaling.

Background Liver cancer is the most malignant type of human malignancies. In recent years, immune therapy that targets the immune check points such as programmed cell death ligand 1 (PD-L1) has achieve great success. Abrine is the dominant alkaloid in Abrus cantoniensis and Abrus precatorius Linn. that exhibited anticancer effect. This work is aimed at studying the effects of abrine in immunity of liver cancer. Methods Cell viability, proliferation, and migration were assessed by CCK-8, Edu, and Transwell assay. Cell apoptosis was checked by flow cytometry. Tumor growth was determined by an in vivo xenograft model. Quantitative real-time PCR assay was conducted to evaluate the levels of KAT5 and PD-L1. T cells and liver cancer cells were cocultured in a Transwell system, and the levels of PD-L1 and PD-1 was checked by flow cytometry. The interaction between KAT5 and PD-L1 was determined by ChIP assay. Results Abrine treatment suppressed liver tumor growth both in vitro and in vivo and simultaneously decreased the level of PD-L1 and KAT5. In the coculture system, treatment with abrine inhibited proliferation and activity of cocultured T cell. KAT5 epigenetically elevated recruitment of H3k27ac and RNA polymerase II to PD-L1 promoter region. Ectopic expression of KAT5 and PD-L1 reversed the function of abrine on tumor growth and T cell function. Conclusion Abrine modulated growth and apoptosis of liver cancer cells and regulated proliferation and activation of T cells through the KAT5/PD-L1 axis.

Indole and quinolizidine alkaloids from blue lupin leach to agricultural drainage water

Phytotoxins are produced in plants including agricultural crops. Lupins and other plants of the Fabaceae family produce toxic alkaloids. These alkaloids have been studied in food and feed, however, the environmental fate of alkaloids produced by cultivated lupins is largely unknown. Therefore, we conducted an agricultural field experiment to investigate the occurrence of indole and quinolizidine alkaloids in lupin plant tissues, soil, soil pore water and in drainage water. During the field experiment, alkaloids were regularly quantified (median concentrations) in lupin (13–8.7 × 103 ng/g dry weight (dw)), and topsoils at depth 0–5 cm (0.1–10 ng/g dw), and depth 15–30 cm (0.2–8.5 ng/g dw), soil pore water (0.2–7.5 ng/L) and drainage water samples (0.4–18 ng/L). Lupanine was the dominant alkaloid in all collected samples. Cumulative amounts of alkaloids emitted via drainage water were around 0.1–11 mg/ha for individual alkaloids over one growing season. The total cumulative amount of alkaloid in drainage water was 14 mg/ha, which is a very small amount compared to the mass of alkaloid in the lupin biomass (11 kg/ha) and soil (0.02 kg/ha). Nearly half of the alkaloids were exported in the drainage water during high flow events, indicating that alkaloids transport preferentially via macropores. These findings indicate that drainage from lupin cultivated areas contribute to surface water contamination. The environmental and ecotoxicological relevance of alkaloids as newly identified aquatic micropollutants in areas with agricultural activities have yet to be assessed.

Development of a specific monoclonal antibody-based icELISA for detection of arecoline in traditional Chinese medicines and fresh areca nuts

ABSTRACT Arecoline, the dominant alkaloid existing in areca nuts, is an addictive substance and classified as a Group 2B potential human carcinogen. Currently, the detection of arecoline is mostly dependent on chromatography-based approaches, which are time-consuming and expensive. We used arecaidine as a hapten to produce a highly specific monoclonal antibody (mAb) against arecoline. An indirect competitive enzyme-linked immunosorbent assay (icELISA) was developed using the mAb-A5H12, to detect arecoline in traditional Chinese medicines and fresh areca nuts. The icELISA indicated that the half maximum inhibition concentration (IC50) for arecoline was 67.9 ng/mL, with a working range of 10.1–502.6 ng/mL and a limit of detection (LOD) of 3.6 ng/mL. High-performance liquid chromatographic (HPLC) confirmed the accuracy and the working range of icELISA, suggesting that the icELISA approach based on the arecoline specific antibody could be a widely applicable and easy operation method in detection of arecoline in foods and medicines.

The Cultivation of Chelidonium majus L. Increased the Total Alkaloid Content and Cytotoxic Activity Compared with Those of Wild-Grown Plants.

The effect of cultivation practises on both the phytochemical profile and biological activity of aqueous ethanol extracts of Chelidonium majus L. was studied. Extracts were prepared from aerial parts of the same plant population collected in the wild and grown under organic farming conditions. Both qualitative and quantitative analyses of alkaloids and flavonoid derivatives were performed by LC/MS methods, and the cytotoxicity of lyophilised extracts was studied in B16-F10, HepG2, and CaCo-2 cells. Coptisine was the dominant alkaloid of extracts prepared from wild-grown plants, whereas after cultivation, chelidonine was the most abundant alkaloid. The total alkaloid content was significantly increased by cultivation. Ten flavonol glycoconjugates were identified in C. majus extracts, and quantitative analysis did not reveal significant differences between extracts prepared from wild-grown and cultivated specimens. Treatment with C. majus extracts resulted in a dose-dependent increase in cytotoxicity in all three cell lines. The extracts prepared from cultivated specimens showed higher cytotoxicity than the extracts prepared from wild-grown plants. The strongest cytotoxic effect of cultivated C. majus was observed in B16-F10 cells (IC50 = 174.98 ± 1.12 µg/mL). Cultivation-induced differences in the phytochemical composition of C. majus extracts resulted in significant increases in the cytotoxic activities of the preparations.

Mitragynine: A review of its extraction, identification, and purification methods

Mitragynine is one of the dominant alkaloids presents in the Mitragyna speciosa which possesses several pharmacological properties such as antinociceptive, anti-inflammatory, and anti-cancer. Studies have reported various methods in extracting mitragynine, both conventional and renewable technology combined with acid-base techniques for the enrichment and purification of mitragynine from the extract of M. speciosa. Several chromatography and spectroscopy instruments such as HPLC, LC-MS, GC-MS, and NMR have been used to identify mitragynine and its content in both the extract and fraction mixtures. In this review, we aim to provide insight on how the methods of extraction, purification, and identification of mitragynine have been developed over the last few decades. This report also shows comparison among the various approaches in extracting mitragynine and points out the facts that different methods gave different yields of the compound.

Berberine hydrochloride mitigates acute pancreatitis by suppressing the TLR4/IκBα/NFκB pathway

Severe acute pancreatitis (SAP) usually causes multiple-organ dysfunction syndrome and exhibits a high mortality rate. It has been previously reported that berberine, as a dominant alkaloid, can be effectively used against inflammation. However, there is limited data on the effects of berberine hydrochloride (BBRH) on inflammation in SAP rat models. Male Sprague–Dawley rats were given preliminary intraperitoneal injections of BBRH 30 min prior to retrograde infusion of 5% sodium taurocholate in their biliopancreatic ducts. The rats were sacrificed 12 h after taurocholate administration, and tissues and blood samples were then acquired for histological, chemical, and molecular analyses. The SAP models exhibited enhanced edema, ascitic fluid volume, neutrophil infiltration, serum amylase and lipase levels, and interleukin (IL)-6, tumor necrosis factor-α, and IL-1β levels, and reduced IL-10 concentration, while BBRH administration reversed these changes. Further study showed that in the SAP model, protein and mRNA levels of nuclear factor kappa-light-chain-enhancer of activated B (NFκB) p65 and toll-like receptor 4 (TLR4) were increased and inhibitor of nuclear factor kappa B (IκBα) expression was decreased, while pretreatment with BBRH significantly decreased the activation of the TLR4/IκBα/NFκB pathway. The data obtained displayed that BBRH mitigated acute pancreatitis by suppressing the TLR4/IκB/NFκB pathway.

Reversible Nematostatic Effect of Peganum harmala L (Nitrariaceae) on Meloidogyne javanica

Meloidogyne javanica is considered as the most damaging nematode of vegetables in Morocco. Eco-friendly bionematicides are urgently required for its control. In vitro experiments were carried out to assess the direct effect of bioproducts of Peganum harmala against M. javanica. The bioassay showed extracts to be nematotoxic. Aqueous extracts of P. harmala exhibited reversible nematostatic activity. The estimated ID50 of the most active product in methanolic extracts was 368ppm. HPLC-MS of the methanolic extract revealed that total content of major alkaloids of P. harmala was approximately 12.162±0.637mg/g. Harmine (8.514±0.521mg/g) is the dominant alkaloid. In conclusion, Peganum harmala has a reversible nematostatic activity on second stage juveniles of M. javanica. The effect of P. harmala is due to its possession of a high content of β-carboline alkaloids, which warrant further experimentation. Bioproducts from P. harmala should be exploited through formulations for management of the root knot nematode.

DETERMINATION OF SECONDARY METABOLITES, TOXICITY AND ANTIOXIDANT ACTIVITIES OF BARK EXTRACTS OF ARTOCARPUS LANCEIFOLIUS ROXB

The purpose of study to determine the content of secondary metabolites, toxicity and antioxidant activity of bark extract from Artocarpus lanceifolius Roxb. The extracts were obtained by maceration method using hexane, chloroform, ethyl acetate and methanol solvents, respectively. The extract obtained was tested for phytochemicals, toxicity test using the shrimp Brine Lethality Test (BSLT), antioxidant test using the DPPH (2,2-diphenyl-1- picrylhydrazyl) method. Phytochemical test results showed that n-hexane extract contained terpenoids and steroids while flavonoid and phenol compounds contained in extracts of chloroform, ethyl acetate, and methanol. The dominant alkaloid compounds were found in ethyl acetate and methanol extracts. Toxicity values (LC50) for n-hexane, chloroform, ethyl acetate extract were 1.0853 μg/mL, 0.1635 μg/mL, 0.3615 μg/mL and 0.2609 μg/mL respectively. The IC50 value of free radical scevange activity of chloroform extract, ethyl acetate were 19.66 μg/mL, 15.85 μg/mL, and 19.01 μg/mL respectively.

Gelsemine and koumine, principal active ingredients of Gelsemium, exhibit mechanical antiallodynia via spinal glycine receptor activation-induced allopregnanolone biosynthesis

Gelsemine, the principal active alkaloid from Gelsemium sempervirens Ait., and koumine, the most dominant alkaloids from Gelsemium elegans Benth., produced antinociception in a variety of rodent models of painful hypersensitivity. The present study explored the molecular mechanisms underlying gelsemine- and koumine-induced mechanical antiallodynia in neuropathic pain. The radioligand binding and displacement assays indicated that gelsemine and koumine, like glycine, were reversible and orthosteric agonists of glycine receptors with full efficacy and probably acted on same binding site as the glycine receptor antagonist strychnine. Treatment with gelsemine, koumine and glycine in primary cultures of spinal neurons (but not microglia or astrocytes) concentration dependently increased 3α-hydroxysteroid oxidoreductase (3α-HSOR) mRNA expression, which was inhibited by pretreatment with strychnine but not the glial inhibitor minocycline. Intrathecal injection of gelsemine, koumine and glycine stimulated 3α-HSOR mRNA expression in the spinal cords of neuropathic rats and produced mechanical antiallodynia. Their spinal mechanical antiallodynia was completely blocked by strychnine, the selective 3α-HSOR inhibitor medroxyprogesterone acetate (MPA), 3α-HSOR gene silencer siRNA/3α-HSOR and specific GABAA receptor antagonist isoallopregnanolone, but not minocycline. All the results taken together uncovered that gelsemine and koumine are orthosteric agonists of glycine receptors, and produce mechanical antiallodynia through neuronal glycine receptor/3α-HSOR/allopregnanolone/GABAA receptor pathway.

Interference mechanism of Sophora alopecuroides L. alkaloids extract on host finding and selection of the Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Psyllidae)

Manipulating insect behavior through the deployment of semiochemicals offers a promising opportunity for protecting crops in a sustainable manner. Therefore, there is still a significant opportunity for the development of natural crop protectants as eco-friendly tools in pest management. In this context, the aim of the current investigation is to find a novel prophylactic against the Asian citrus psyllid (ACP) and to gain a better understanding of the host-finding and selection ability of the ACP towards Murraya paniculata seedlings treated with Sophora alopecuroides alkaloids extract (SAAE). Our results indicate that foliar application of SAAE influences the psyllid host-finding and selection process. The behavioral assay with M. paniculata seedlings treated with 15 and 30mg/mL of SAAE, with masked visual cues, revealed that only 6.6 and 10.4% psyllids were able to locate the host in the vials. The results also indicate that citrus psyllids mainly rely on both visual and olfaction in host-finding and selection. In choice settling experiments, psyllids settled almost completely on control seedlings rather than on seedlings treated with SAAE at a concentration of 30mg/mL. Chemical analyses of the alkaloids extract revealed the presence of sophocarpine (33.90%), sophoridine (6.23%), anagyrine (2.77%), matrine (2.38%), lupanine (1.68%) aphylline (0.89%), and sophoramine (0.75%). In further behavioral bioassays with the dominant alkaloids sophocarpine and sophoridine, the alkaloids repelled ACP at higher concentrations of 50 and 70mg/mL as compared to SAAE. Furthermore, the 50mg/mL (1:1, v/v) combination of sophocarpine and sophoridine displayed a synergistic effect and showed the maximum behavioral effect as compared to the individual alkaloid. Based on our results, SAAE makes M. paniculata seedlings unattractive to the psyllids, and therefore, alkaloids could be used in reducing the colonization of citrus plants, subsequently curtailing HLB infection.

Cinchona cells performance in in vitro culture: quinine alkaloid production with application of different elicitors

Quinine is a dominant alkaloid in Cinchona ledgeriana. It is widely used in anti-malaria, anti-cramping, and anti-arrhythmia medication. In addition, it is commercially demanded for its bitter taste in certain soft drinks. The main source of quinine is the bark of Cinchona plant, which consists of 4-7% of the alkaloid. Land use shifting from perennial trees to cash-crops has resulted in a shortage of the plant material for quinine extraction. Plant cell culture has proven its success in producing secondary metabolites, including alkaloids. In principle, plant cells synthesize secondary metabolites when they are exposed to stress conditions. Therefore, in cell culture of C. ledgeriana, two stress-inducing agents i.e. abscisic acid (ABA) and paclobutrazol (PBZ) in combination with mannitol or sorbitol were applied to increase quinine yield. ABA and PBZ depressed the cells growth. Sorbitol caused more stress to cells than mannitol. Its combination with ABA 3 mgL−1 or with PBZ 7 mgL−1, mixed three weeks after culture, produced the highest concentration of quinine followed by mannitol with ABA 3 mgL−1 or PBZ 7 mgL−1 combined at the third week after culture. Cultured cells showed three different shapes: round, oval, and elongated. The elongated shape pre-dominated in the mature cells culture, while round cells pre-dominated in young cells culture. Those mature cells were found to contain alkaloids.

Development of an immunochromatographic strip incorporating anti-mitragynine monoclonal antibody conjugated to colloidal gold for kratom alkaloids detection.

A lateral flow-based immunochromatographic strip was developed for the rapid detection of mitragynine (MG), a dominant alkaloid found in the leaves of kratom. Monoclonal antibody (mAb) against MG (anti-MG mAb) was conjugated to colloidal gold and used as a recognition probe. MG-ovalbumin conjugate (MG-OVA) and goat anti-mouse IgG were immobilized on the strip to produce a test zone and control zone, respectively. Based on the principle of a competitive assay, MG in a test sample competed with MG-OVA resident in the test zone to bind with colloidal gold-anti-MG mAb, resulting in an inverse relation of color intensity at the test zone and MG amount. The limit of detection (LOD) of the immunochromatographic strip is determined at 1mg/mL of MG by visual assessment and 0.60mg/mL by Image J analysis. The developed immunochromatographic strip can determine MG in kratom cocktails and kratom leaf samples. It could serve as a rapid and simple diagnostic kit for the detection of MG in kratom samples.