Insecticidal activity of Stemona collinsiae root extract against Parasarcophaga ruficornis (Diptera: Sarcophagidae)

Larvicidal activity of Stemona collinsiae root extract against Musca domestica and Chrysomya megacephala

Musca domestica and Chrysomya megacephala, considered synanthropic insects, are medically important flies, as they transmit vector-borne diseases to humans and animals. In Thailand, Stemona (Stemonaceae) plants have been traditionally used as insecticides. This study was designed to determine the larvicidal activity of S. collinsiae root extract against M. domestica and C. megacephala larvae. A 70% ethanol crude extract from S. collinsiae roots was tested against the third-instar larvae of both species using direct and indirect contact methods. The development and mortality rates of the insects were observed, and the LC values were calculated. The extract caused irregular development in both species, shown as segmental puparia that could not emerge as adult flies. The LC50 values of the extract against M. domestica tested by direct and indirect contact methods were 0.0064 ± 0.0005 mg/larva and 0.0165 ± 0.0002 mg/cm2/larva, respectively. In the case of C. megacephala, the LC50 value determined by the indirect contact method was 1.0500 ± 0.0001 mg/cm2/larva. The ethanolic root extract of S. collinsiae was able to kill the larvae of both species after dermal administration. It is of interest to develop S. collinsiae root extract as a natural fly control biopesticide.

Oral toxicity of various Stemona collinsiae crude extracts against nymph and adult stages of American cockroach, Periplaneta americana (Dictyoptera: Blattodea)

Stemona collinsiae exhibits insecticidal resistance against various pests and insect vectors. However, insecticidal activity of S. collinsiae roots has not been tested for some insect vectors, including the American cockroach, Periplaneta americana. The synanthropic insect P. americana is a reservoir of pathogenic and non-pathogenic microorganisms and a cause of infectious diseases and cockroach allergy. This important vector transmits microorganisms to animals and humans to cause vector-borne diseases. This research involved detection of the nymphicidal and adulticidal activities of S. collinsiae root extracts against P. americana through oral administration. The effects of hexane, dichloromethane, ethanol, and water crude extracts were tested on final instar nymphs and adult P. americana. After P. americana ingested bait containing hexane and dichloromethane crude extracts, signs of toxicity occurred, such as hind leg shaking, whole-body tremor, immobility, abdomen swelling, and death. At 48 h, the nymphs and adult P. americana that ingested dichloromethane crude extract-containing bait showed corrected mortality of 65%-100% and 20%-100%, respectively. Whereas none of the nymphs and adult P. americana that ingested the water crude extract-containing bait died (0% corrected mortality). When we dissected alimentary canals of the dead P. americana that had ingested dichloromethane and hexane crude extract-containing baits, the foreguts were found to be swollen. TLC analysis showed the dichloromethane and hexane crude extracts contained the alkaloid didehydrostemofoline and unknown fluorescent substances. Phytochemicals from crude extracts were detected in extracts of dissected alimentary canals using thin-layer chromatography, and didehydrostemofoline alkaloid and unknown fluorescent substances were found in cockroaches that ingested dichloromethane- and hexane-containing baits. The cause of death of P. americana may be attributed to alkaloids and synergistic effects of other substances in S. collinsiae root extract. Mechanisms of action might include several pathways involved in nervous system function. Thus, dichloromethane and hexane crude extracts can be developed as alternative active ingredients in a natural insecticide for cockroach control.

The traditional uses, phytochemistry, and pharmacology of Stemona species: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Plants of genus Stemona (Stemonaceae) have been long used locally and traditionally in many South and East Asian counties to relieve cough, dispel phlegm, prevent asthma, control pests, diminish inflammation, decrease pain, and treat some cutaneous diseases.

AIM OF STUDY

This review provided comprehensive and up-to-date information about botanic characterization and distribution, ethnopharmacology, secondary metabolites, pharmacological activities, and toxicology of plants of genus Stemona to explore the scientific potential and future therapeutic potential of the plants.

MATERIALS AND METHODS

This article conducted a literature review on information about the Stemona species in multiple electronic databases, including PubMed, Web of Science, Wiley, Science Direct, Elsevier, Google Scholar, ACS publications, SpringerLink, and China National Knowledge Internet. Information was also derived from other literature sources (e.g. Chinese Pharmacopoeia, 2015 edition, Chinese herbal classic books, PhD and MSc thesis). Plant names were validated by "The Plant List" (www.theplantlist.org). All studies of the genus Stemona were included in this review until March 2020.

RESULTS

Our comprehensive analysis of the scientific literatures indicated that many Stemona species are popular and valuable herbal medicines with therapeutic potentials to treat various ailments. Phytochemical analyses identified alkaloids and stilbenoids as the major bioactive substances of Stemona species. Numerous studies have shown that the extracts and secondary metabolites isolated from these plants have a wide range of pharmacological activities, including insecticidal and antifeedant, antitussive, anti-inflammatory, anticancer, antimicrobial, and antivirus activities.

CONCLUSION

Though plants of genus Stemona have been put to enormous traditional uses, the pharmacological studies conducted were insufficient. Therefore, more secondary metabolites need to be studied for more detailed pharmacological studies. Further studies are also required to establish the mechanisms which mediate the plants' bioactivities in relation to the medicinal uses as well as investigate any potential toxicity for future clinical studies.

Cytotoxic and larvicidal activities of Stemona alkaloids from the aerial parts and roots of Stemona curtisii Hook.f

A new Stemona alkaloid glycoside derivative, 6-hydroxy-5,6-seco-stemocurtisinoside (4), was isolated from the ethanolic extract of the aerial parts of Stemona curtisii Hook.f., together with stemocurtisine (1), (11Z)-1',2'-didehydrostemofoline (2) and 6-hydroxy-5,6-seco-stemocurtisine (3). Whereas, stemocurtisine (1), stemocurtisinol (5) and oxyprotostemonine (6) were isolated from the roots. Their structures were elucidated using 1D and 2D NMR spectroscopy as well as MS experiments. The extract and the pure isolated compounds were evaluated for their cytotoxicities and their larvicidal activities against the dengue vector, Aedes aegypti. The alkaloid 2 showed the strongest larvicidal activity with a LC₅₀ value of 2.44 µM. While the alkaloid 3 exhibited cytotoxicity against MCF-7 and KB cells (IC₅₀ values of 62.52 and 18.82 µM, respectively) and showed no significant cytotoxicity against Vero cells. Additionally, quantitative analysis of the most active compounds; 2 and 3 in the crude extracts was also performed by HPLC.

Using UPLC-QTOF-MS Method to Analyse the Spot Constituents of the Thin Layer Chromatograms for Chuzhou Stemona sessilifolia (Miq.) Miq

A simple, rapid, and highly sensitive analytical method was established for identification of constituents in the spot of the thin layer chromatogram of Chuzhou Stemona sessilifolia (Miq.) Miq. (Chuzhou S. sessilifolia) with ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). The technology was applied to systematically analyze and detect the targeted spots. Compared with the fragmentation behaviors of more than thirty reference constituents, the possibly existing compounds of the target spots were identified or tentatively identified by their exact masses and diagnostic fragment ions. Finally, the four clear spots of the thin layer chromatograms of Chuzhou S. sessilifolia were screened and identified of possible molecular formula and structures.