Effects of plumbagin on development of the parasitic nematodes Haemonchus contortus and Ascaris suum

Structural Insights and Pharmaceutical Relevance of Plumbagin in Parasitic Disorders: A Comprehensive Review

Recently, natural products have been became the center of attraction for the scientific society and exploration of their biologically abilities is proceeding continuously. In search for novel antiparasitic agents with an objective of protecting humans from parasitic infections, the present work was focused on naphthoquinones possessing antiparasitic activity. Among naphthoquinones, plumbagin is one of the secondary metabolites exhibiting diverse biological properties such as antibacterial, antimalarial, antiinflammatory, insecticidal and antiparasitic. Plumbagin is reported to have antischistosomiasis, anti-haemonchosis, anti-fascioliasis, antiotoacariasis, anti-leishmaniasis, antimalaria, antiallergic and anthelmintic activities. Besides, various methods of extraction of plumbagin from different methods, their effectiveness against different parasites, and the structure-activity relationship reported by different researchers. This work highlight on recent advancements in the phytochemistry of plumbagin, studies associated with various biological activities. The structure-activity relationship studies have also been summarized. To conclude, present review could be beneficial for the scientific community to get better insight into medicinal research of plumbagin and may provide a new horizon for the rational design of plumbagin based compounds.

Anthelmintic Activity of Extracts and Active Compounds From Diospyros anisandra on Ancylostoma caninum, Haemonchus placei and Cyathostomins

The present study aimed to evaluate the anthelmintic activity of leaf and bark extracts of Diospyros anisandra collected during different seasons and their major constituents on eggs of Ancylostoma caninum, Haemonchus placei, and cyathostomins. Specifically, the eclosion inhibition of the methanolic extracts of the leaves and bark of D. anisandra collected during the dry and rainy seasons (600–37.5 μg/ml) were evaluated in addition to the fractions, sub-fractions (300–37.5 μg/ml) and active major constituents (150–2.3 μg/ml). The rainy season bark extract had the highest percentage of eclosion inhibition (PEI) against the evaluated nematodes (≥ 90% at 75 μg/ml) along with high ovicidal activity (90.0 to 93.4% at 75 μg/ml). The purification of the rainy season bark extract showed that its biological activity came from the non-polar n-hexane fraction (≥ 93% at 75 μg/ml). The bioguided fractionation pointed to sub-fraction 5 as having the highest anthelmintic activity against the three evaluated genera of nematodes (PEI ≥ 93% at 37.5 μg/ml). Gas chromatography and mass spectrometry revealed that the major constituent in sub-fraction 5 was plumbagin. Upon evaluation, plumbagin was confirmed to be responsible for the anthelmintic activity of D. anisandra, with a PEI ≥ 90% at 2.3 μg/ml on the three evaluated nematodes. Additionally, the compounds betulin and lupeol in the bark of D. anisandra were evaluated but presented low anthelmintic activity (PEI ≤ 5.3% at 2.3 μg/ml). In conclusion, the rainy season bark extract of D. anisandra exerts a high ovicidal activity against the eggs of the three studied nematodes. Plumbagin is the active compound responsible for this activity and represents a potential alternative for the control of different genera of gastrointestinal nematodes given the current scenario of anthelmintic resistance.

Nematicidal effect of plumbagin on Caenorhabditis elegans: a model for testing a nematicidal drug

Plumbagin, (5-hydroxy-2-methyl-1,4-naphthoquinone), a natural substance found in the roots of plant species in the genus Plumbago, has been used as a traditional medicine against many diseases. In this study, Caenorhabditis elegans was used as a model for testing the anthelmintic effect of plumbagin. The compound exhibited a nematicidal effect against all stages of C. elegans: L4 was least susceptible, while L1 was most susceptible to plumbagin with an LC(50) of 220 and 156 μM, respectively. Plumbagin inhibited C. elegans development from L1 to adult stages with an IC(50) of 235 μM, and body length was also reduced at concentrations of 25 and 50 μg/ml. Brood sizes decreased from 203±6 to 43±6 and 18±3 eggs per hatch in plumbagin-treated worms at 10, 25, 50 μg/ml, respectively. Furthermore, plumbagin was lethal to strains resistant to the nematicides levamisole, albendazole, and ivermectin, indicating that it possesses a strong and unique nematicidal action. Plumbagin decreased the number of mitochondria in hypodermal and intestinal cells and body wall muscles and damaged the ultrastructure of these tissues. Taken together, plumbagin may be a new drug against parasitic nematodes.

Differential toxicity of juglone (5-hydroxy-1,4-naphthoquinone) and related naphthoquinones to saturniid moths

The preferred hosts of the saturniid mothActias luna include members of the Juglandaceae, whose foliage contain the toxin juglone (5-hydroxy-1,4-naphthoquinone). The performance ofActias luna andCallosamia promethea was compared when fourth-instar larvae of each were fed birch foliage, a mutually acceptable food plant, or birth supplemented with 0.05% (w/w) juglone.A. luna fed juglone exhibited no changes in developmental time or mortality compared to a diet without juglone. In contrast, juglone-supplemented diets, when fed toC. promethea, caused negative growth rate, and a 3.6-fold decrease in consumption rate. The performance ofA. luna also was compared on birch and walnut; larvae developed and grew more rapidly on an all-walnut vs. an all-birch diet. To examine the effect of 1,4-naphthoquinone structure onA. luna survival, first instars were fed on birch supplemented with varying concentrations of juglone (J), menadione (M), plumbagin (P), or lawsone (L). In diets supplemented at 0.05% (w/w), none of the compounds produced effects significantly different from controls. In diets supplemented at 0.5% (w/w), the treatments produced significant toxic effects in the order P>M=L>J for mortality, and P>L>M=J for increased developmental time. Late-instarA. luna are clearly resistant to juglone compared toC. promethea, and early-instarA. luna are resistant to several related 1,4-naphthoquinones. These results suggest a chemical basis for host choice among saturniids. In addition, the luna-walnut system may be a valuable model for studying quinone detoxication.

Paramphistomum cervi: the in vitro effect of plumbagin on motility, survival and tegument structure

Paramphistomiasis causes enteritis and anemia in livestocks and result in substantial production and economic losses. It is considered a neglected tropical disease, with no effective trematodicidal compound for treatment. Plumbagin (PB), a compound founds to be rich in the roots of Plumbago indica, is a naphthoquinone derivatives which can induce oxidative stress in parasites. In this study we have evaluated the anthelmintic activity of PB against adult Paramphistomum cervi by incubating the parasites in M-199 medium containing 0.1, 1.0, 10 and 100 μg/ml of the PB, and albendazole (ABZ) at the concentration of 100 μg/ml as the positive control, for 3, 6, 12 and 24 h, using relative motility (RM) assay and observed by scanning electron microscopy (SEM). After 12 h exposure with 100 μg/ml ABZ, flukes showed decreased contraction and motility. At 24 h incubation they showed only active movement of some part of the body. The PB-treated flukes at all concentrations showed rapid decrease of motility at 3 h incubation. In 0.1, 1.0 and 10 μg/ml of PB, the RM values were decreased sharply from 3 to 12 h, and then they were killed since 12 h in the incubation with 10 μg/ml of PB. The highest parasite mortality was found as early as 3h when they were incubated with 100 μg/ml of PB. The morphological changes on the tegumental surface were similar in both flukes treated with ABZ and PB, which sequentially comprised of swelling, followed by blebbings that later ruptured, leading to the erosion and desquamation of the tegument syncytium. As the result, lesions were formed which exposed the basal lamina. The damage appeared more severe on the ventral than the dorsal surface, and earlier on the anterior part and lateral margins of middle third when compared to the posterior part of the parasites's bodies. The severity and rapidity of the damages were enhanced with increasing concentration of PB, which showed stronger activity than ABZ. Hence, PB has a potential to be an anthelmintic drug against adult P.cervi.

Induction of topoisomerase II-mediated DNA cleavage by the plant naphthoquinones plumbagin and shikonin

Plumbagin and shikonin, plant metabolites which have naphthoquinone structures, induced mammalian topoisomerase II-mediated DNA cleavage in vitro. Treatment of a reaction mixture containing these naphthoquinones and topoisomerase II at an elevated temperature (65 degrees C) resulted in a great reduction in DNA cleavage, suggesting that the mechanism of the topoisomerase II-mediated DNA cleavage induced by these naphthoquinones is through formation of a cleavable complex, as seen with antitumor agents such as 4'-(9-acridinylamino)methanesulfon-m-anisidide and demethylepipodophyllotoxin ethylidene-beta-glucoside. Lawson and lapacol, which are structurally related plant metabolites with naphthoquinone moieties, could not induce topoisomerase II-mediated DNA cleavage. Plumbagin and shikonin induced a similar DNA cleavage pattern with topoisomerase II which was different from the cleavage patterns induced with other known topoisomerase II-active drugs. A DNA-unwinding assay with T4 DNA ligase showed that shikonin, lawson, and lapacol did not intercalate into DNA, while plumbagin and 2-methyl-1,4-naphthoquinone intercalate into DNA, but to a lower degree than 4'-(9-acridinylamino)methanesulfon-m-anisidide does.