Review Article Review of Compounds and Pharmacological Effects of Delphinium

Plants of Delphinium are herbal medicine used in the Tibet region with whole grass as a drug, which have the eﬀects of analgesic, antibacterial, antipyretic, and anticancer. The main bioactive compounds are alkaloids, ﬂavonoids, and sterols. This review summarized the compounds and pharmacological eﬀects of Delphinium and provides a reference for further research on Delphinium .


Introduction
Delphinium of the Ranunculaceae family is widely distributed in the North temperate zone, with about 350 species worldwide. 173 species (150 endemic) of Delphinium are distributed in China [1]. Delphinium is composed of subgen. Delphinastrum, subgen. Delphinium, and subgen. Oligophyllon, in the world, of which subgen. Delphinastrum has the most species [2]. In China, there are 18 species of Delphinium used as folk medicine, which are used to treat bruises, rheumatism, toothache, and enteritis. In addition, four species of Delphinium can be used as soil pesticides for their effects of killing lice, mosquitoes, and fly larvae [3]. e main compounds of Delphinium are diterpenoid alkaloids, and most of them have physiological activities [4]. In addition, Delphinium also contains chemical constituents such as flavonoids and sterols. In recent years, with the development of analysis methods and increasing focus on Delphinium, more and more chemical constituents and pharmacological activities of Delphinium had been researched. In this paper, the chemical constituents and pharmacological effects of Delphinium were reviewed in order to improve the development and utilization of the Delphinium resources.
ere are abundant diterpenoid alkaloids in Delphinium, which can be classified into C-18 diterpenoid alkaloids, C-19 diterpenoid alkaloids, and C-20 diterpenoid alkaloids according to the carbon skeleton configuration [5]. Characteristic quaternary carbon signal and substituent signal are important information to distinguish different diterpene alkaloids.
At present, 155 alkaloids were isolated from Delphinium, and the details are shown in Tables 1-3 and Figures 4-6.  Based on the references listed in Tables 1-3, it can be summarized that D. anthriscifolium varietas and D. elatum and its varietas have been further studied in chemistry.

Amide Alkaloids.
e typical groups of amide alkaloids are acyl groups. 9 amide alkaloids were isolated from Delphinium, and the details are shown in Table 4 [49]) was isolated from D. anthriscifolium var. majus. e structure is shown in Figure 8.

Other Compounds.
Delphinium also contains compounds such as flavonoids and sterols. In recent years, other compounds isolated from Delphinium had also been reported, and a total of 13 nonalkaloids (Table 5 and Figure 9) were isolated from Delphinium.

Biological Activities
Plants of Delphinium are used with whole grass as medicine. According to the ancient Tibetan medicine Jingzhubencao, plants of Delphinium had analgesic, anti-inflammatory, and insecticidal effects [9]. Literature studies showed that plants of Delphinium have many pharmacological effects including antibacterial, antiepileptic, detoxification, and Alzheimer's disease treatment. In this section, this paper reviews the research studies on the antibacterial, analgesic, anti-inflammatory, antidepressant, and anticancer effects of Delphinium.
3.1. Antibacterial Activity. Hari et al. found that anthriscifoldine C (5.0 mg/mL) from D. brunonianum had a good inhibiting effect on Bacillus subtilis, Escherichia coli, and Salmonella flexnari, and its MIC were 24.0 µM, 23.4 µM, and 24.2 µM, respectively, in vitro [61]. Ren et al. carried out the bacteriostatic test on the total alkaloids extracted from the roots of Delphinium and found that the MIC of the total alkaloids extracted on S. aureus and Aspergillus niger was 50 mg/mL in vitro [62]. e experimental results showed that the response time of rats given D. denudatum ethanol extract and methanol fraction was longer than that of the propylene glycol group, and the effects of the high doses of the ethanol extract (600 mg/kg) and methanol fraction (400 mg/kg) were equal to that of the positive control group, indicating that        [47] Journal of Chemistry 5  Journal of Chemistry swelling in outbred male rats. On the 14th day, the rats in the total alkaloids (0.05 mg/kg) treatment group of Delphinium had no pain when their joints were bended, which indicated a good analgesic effect of Delphinium [64]. rough the hotplate method and the acetic acid writhing method, Suslov et al. found that the water extract (0.5 g/kg) and the alcohol extract (0.25 g/kg) of D. grandiflorum L. var. leiocarpum could prolong the pain threshold of mice, which was similar to the effect of acetaminophen (0.2 g/kg), and performed a good analgesic effect [65].

Anti-Inflammatory Activity.
Nesterova et al. found that the alkaloids and flavonoids in Delphinium had a good inhibitory effect on the inflammatory response through the experiment of the mice peritonitis model in the inflammatory exudation phase in vivo. Aqueous fraction of flavonoids (25.0 mg/kg) had a good therapeutic effect on the edema reaction caused by histamine (0.1%), and alkaloids (0.05 mg/kg) showed a good anti-inflammatory effect on the inflammatory reaction caused by 5-hydroxytryptamine (0.5 mg/kg) [66]. Andreeva and Liu established an acute inflammation model with increased capillary permeability induced by acetic acid in ICR male mice, and the results showed that the high-(1.5 g/kg), medium-(1.0 g/kg), and low-dose groups (0.5 g/kg) of the total flavonoids extracted from D. grandiflorum with ethanol had good anti-inflammatory activity [67].  3.6. Antipulmonary Fibrosis Activity. In the study on pulmonary fibrosis induced by bleomycin in SD rats, Lin et al. found that after 14 days of gavage with 4 g/kg, 2 g/kg, and 1 g/kg extracts of D. trichophorum, the expression of collagen in the tissues during the pathological process of pulmonary fibrosis could be inhibited and the symptoms of pulmonary fibrosis in rats could be improved [71]. lasiocarpum on Spodoptera exigua, and the results showed that the chemical shawurensine had a strong antifeedant activity with an EC 50 of 0.45 mg/cm 2 [31]. González and Guadaño extracted 5 alkaloids from Delphinium for activity determination against Spodoptera littoralis and Leptinotarsa decemlineata by choice feeding assays, and the results showed that cardiopetamine had the strongest activity against S. littoralis with the EC 50 of 5.48 nmol/cm 2 and 15acetylcardiopetamine had the strongest activity against L. decemlineata with the EC 50 of 12.86 nmol/cm 2 [72].

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Journal of Chemistry  Although there are many research studies, the pharmacological effects on the antibacterial, analgesic, anti-inflammatory, antidepressant, anticancer, antipulmonary fibrosis, antifeedant, and antiparasite effects of Delphinium are mainly on the crude extracts and few on compounds.

Future Prospects
e genus Delphinium is rich in new and novel compounds, but the current research is only focused on several species. In the future, more new compounds should be investigated from other species in depth. e pharmacological effects of Delphinium are extensive, but the current research is limited to extracts, so it is necessary to focus on the effects of the compounds from Delphinium and the structure-activity relationship in the future.
Data Availability e data supporting this article are from previously reported studies, which have been cited. e data are available from the corresponding author upon request.