C19-diterpenoid Alkaloids Research Articles

Diterpenoid alkaloids from the Aconitum episcopale levl. And their chemotaxonomic significance

Nineteen diterpene alkaloids were isolated from Aconitum episcopale Levl. by phytochemical methods, including seventeen aconitine-type C19-diterpenoid alkaloids (1–17) and two bis-diterpenoid alkaloids (18–19). Their structures were determined by NMR analysis and comparison with the reported data. Among them, eleven compounds (2, 4–5, 7–8, 10–11, 16–19) were isolated from this species for the first time, of which five compounds (4, 10–11, 18–19) were obtained from series Volubilia for the first time. In addition, the chemotaxonomic significance of these diterpene alkaloids is generalized.

A New C19-Diterpenoid Alkaloid from Salted Aconiti Lateralis Radix Praeparata

A New C19-Diterpenoid Alkaloid from Salted Aconiti Lateralis Radix Praeparata

Antinociceptive diterpenoid alkaloids from the roots of Aconitum austroyunnanense

A phytochemical investigation on the roots of Aconitum austroyunnanense afforded three undescribed aconitine–type C19–diterpenoid alkaloids, austroyunnanines A–C (1–3). Structural elucidation of all the compounds were performed by spectral methods such as 1 D and 2 D (1H–1H COSY, HMQC, and HMBC) NMR spectroscopy. The isolated alkaloids were tested in vivo for their antinociceptive properties. Consequently, austroyunnanine B (2) exhibited significant antinociceptive effect and its ID50 value (48.0 μmol/kg) was 2-fold less than those of the positive control drugs aspirin and acetaminophen.

Diterpenoid alkaloids isolated from Delphinium trichophorum alleviate pulmonary fibrosis via the TGF-β/Smad pathway in 3T6 and HFL-1 cells

Delphinium trichophorum Franch (DTF), a species endemic to China, has been widely used for centuries in Tibet as an indigenous medicine for treating cough, pneumonia, and pulmonary fibrosis. Hetisine-type C20-diterpenoid alkaloids have been reported to be characteristic and active ingredients. Herein, five ones with relatively high contents in D. trichophorum, including 2α,11α,13β-triacetylhetisine (DTF1), trichodelphinine A (DTF2), trichodelphinine D (DTF3), 2α-acetyl-11α,13β-dihydroxyhetisine (DTF4), and trichodelphinine C (DTF5), were investigated for anti-fibrosis effects using fibroblasts induced by TGF-β1 or LPS for the first time. The results showed that all five tested compounds decreased hydroxyproline (HYP) levels and inhibited the abnormal proliferation of 3T6 and HFL-1 cells induced by either TGF-β1 or LPS. Moreover, DTF1 and DTF2 attenuated the production of collagen (Col-1 and Col-3) at relatively low doses, suggesting their higher efficiency among the five alkaloids. Based on large-scale ligand-based pharmacophore modeling, TGFBR1 was screened as a potential target for these tested alkaloids. The molecular docking results also exhibited high-affinity interactions between TGFBR1 and five alkaloids, especially DTF1 and DTF2. Further experiments revealed that DTF1 and DTF2 could inhibit the expression of TGF-β1 and α-SMA and the phosphorylation of Smad3 and Smad4 while restoring the expression of Smad7 protein. Overall, DTF1 and DTF2 may reduce collagen generation and delay the development of pulmonary fibrosis by inhibiting the activation of the TGF-β/Smad signaling pathway. Our results provide experimental and theoretical evidence for DTF1 and DTF2 as superior candidates for further development of anti-fibrotic drugs.

Gyalanunines a, a New Hetisine–Type C20–Diterpenoid Alkaloids with a Hemiacetal Ring from Delphinium Gyalanum

Gyalanunines a, a New Hetisine–Type C20–Diterpenoid Alkaloids with a Hemiacetal Ring from Delphinium Gyalanum

Eleven new C19-diterpenoid alkaloids from Delphinium elatum cv. Pacific Giant.

Diterpenoid alkaloids, the main components of plants of the genera Aconitum, Delphinium, and Garrya, are a group of natural products with notable chemical properties and biological activities. Several C19-diterpenoid alkaloid components from Delphinium elatum cv. Pacific Giant, as well as their derivatives, exhibited cytotoxic activity against lung, prostate, cervical, and vincristine-resistant cervical cancer cell lines. In the current phytochemical investigation on the seeds of D. elatum cv. Pacific Giant, eleven new C19-diterpenoid alkaloids, elapaciline (1), meladine (2), melapacitine (3), iminoeladine (4), 19-oxopaciline (5), 19-oxopacinine (6), N-deethyldelpheline (7), N-deethylpacinine (8), N-deethyl-19-oxoeladine (9), N-deethyl-N-formyleladine (10), and N-deethyl-N-formyldelpheline (11), together with 15 known C19-diterpenoid alkaloids were isolated. Their structures were elucidated by extensive spectroscopic methods including NMR (1D and 2D), IR, and MS (HRMS). Three known diterpenoid alkaloids, 6-dehydrodelcorine (12), delelatine (23), and 6-dehydroeldelidine (24), were isolated for the first time from this plant. Six of the new C19-diterpenoid alkaloids (2, 4-7, and 11) and three of the known diterpenoid alkaloids (18, 23, and 24) were evaluated for cytotoxic activity against five human tumor cell lines.

Diterpenoid alkaloids from Delphinium forrestii var. viride and their anti-inflammation activity

Six undescribed diterpenoid alkaloids including five C19-diterpenoid alkaloids forrestlines A-E, and one C20-diterpenoid alkaloid forrestline F, together with nine known alkaloids have been isolated from the whole herbs of Delphinium forrestii var. vride. Their structures were elucidated by spectroscopic data, and their inhibitory activities on NO production stimulated by LPS in RAW264.7 macrophage cells were determined. Then, forrestline F, with the strongest inhibitory activity (IC50 of 9.57 ± 1.43 μM), was selected to study its possible anti-inflammatory mechanism. ELISA results showed that forrestline F suppressed inflammatory cytokines, including interleukin-1β (IL-1β), tumor necrosisfactor-α (TNF-α), and interleukin-6 (IL-6). Moreover, forrestline F could down-regulate LPS-induced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) by western blotting assay. It also inhibited expression of phosphorylation of MAPKs (including p-p38, p-ERK and p-JNK), and NF-κB p65, and decreased ROS accumulation by upregulating the expression of HO-1 expression via nuclear translocation of Nrf2. In conclusion, forrestline F showed anti-inflammatory effect by inhibiting NF-κB/MAPK and Nrf2/HO-1 signaling pathway. Therefore, forrestline F could be a promising molecule for the development of anti-inflammatory agents in the future.

Three New C19-Diterpenoid Alkaloids from Aconitum novoluridum.

Three new aconitine-type C19-diterpenoid alkaloid namely novolunines A (1), B (2), and C (3), along with fifteen known diterpenoid alkaloids were isolated from the roots of Aconitum novoluridum, whose phytochemical investigations have never been reported before. The structures of three new alkaloids were established on the basis of spectra data (high-resolution electrospray ionization (HR-ESI)-MS, IR, one dimensional (1D)- and 2D-NMR). Noteworthily, novolunines A (1) and B (2) are two diterpenoid alkaloids bearing conformational isomerism. In addition, the diterpenoid alkaloids 1-3 did not show any anti-acetylcholinesterase (AChE) or anti-inflammatory activities.

Total Syntheses of the C19 Diterpenoid Alkaloids (-)-Talatisamine, (-)-Liljestrandisine, and (-)-Liljestrandinine by a Fragment Coupling Approach.

The C19 diterpenoid alkaloids (C19 DTAs) are a large family of natural products, many of which modulate the activity of ion channels in vivo and are therefore of interest for the study of neurological and cardiovascular diseases. The complex architectures of these molecules continue to challenge the state-of-the art in chemical synthesis, particularly with respect to efficient assembly of their polcyclic ring systems. Here, we report the total syntheses of (−)-talatisamine, (−)-liljestrandisine, and (−)-liljestrandinine, three aconitine-type C19 DTAs, using a fragment coupling strategy. Key to this approach is a 1,2-addition/semipinacol rearrangement sequence which efficiently joins two complex fragments and sets an all-carbon quaternary center.

Isolation, identification, and activity evaluation of diterpenoid alkaloids from Aconitum sinomontanum

A phytochemical study led to the isolation of 25 diterpenoid alkaloids from Aconitum sinomontanum, of which six were described for the first time. Among them compounds 1–3 are anhydrolycoctonine derivatives, rare rearranged aconitine-type C19-diterpenoid alkaloids. To our best knowledge, less than ten of this type of alkaloids were isolated just from the genus Aconitum. The structures of these unreported compounds were elucidated by extensive analysis of NMR spectroscopic data and X-ray diffraction. The biological activities of compounds 1–3, 5–9, and 12–25 were evaluated. Among the tested compounds, compounds 2 and 17 showed potent inhibitory effect on the capsaicin (selective TRPV1 agonist) mediated activation of transient receptor potential vanilloid 1 (TRPV1) channels expressed in HEK-293 cells with inhibition rate of 31.78% and 30.94% at the concentration of 10 μM. Compounds 1–3, 5–9, 13, and 18–25 exhibited weak cytotoxic activity against human tumor cell lines NCI–H226 and MDA-MB-231 with inhibition rate over 10% at the concentration of 10 μM. Compound 16 showed most inhibitory effect on the expression of Nrf2 (NF–E2-related factor-2)-regulated gene with inhibition rate of 25% at the concentration of 20 μM.

Antinociceptive C19–diterpenoid alkaloids from the root of Aconitum episcopale

A chemical investigation on the roots of Aconitum episcopale afforded three undescribed aconitine–type C19–diterpenoid alkaloids, episcopalines A–C (1–3). The structures of the new compounds were elucidated by spectroscopic analysis (NMR, IR, UV, and MS). The isolated alkaloids were tested in vivo for their antinociceptive properties. As a result, episcopaline B (2) showed potent antinociceptive effect and its ID50 value (55.0 μmol/kg) was 2-fold less than those of the positive control drugs aspirin and acetaminophen.

Asymmetric Total Syntheses of (+)-Davisinol and (+)-18-Benzoyldavisinol: A HAT-Initiated Transannular Redox Radical Approach.

The first and asymmetric total syntheses of two C11-oxygenated hetisine-type diterpenoid alkaloids, namely, (+)-davisinol and (+)-18-benzoyldavisinol, is described. The concise synthetic approach features a HAT-initiated transannular redox radical cyclization, an ODI-Diels-Alder cycloaddition, and an acylative kinetic resolution. By incorporating an efficient late-stage assembly of the azabicycle, our strategy would streamline the synthetic design of C20-diterpenoid alkaloids and pave the way for their modular syntheses.

Components and Pharmacodynamical Mechanism of Yinfupian Based on Liquid Chromatography-Mass Spectrometry and Proteomics Analyses.

Objective: According to the treatment records of Yang deficiency syndrome (YDS) with characteristic decoction pieces of lateral root of Aconitum carmichaelii—Yinfupian (YF) in traditional Chinese medicine prepare school, known as “Jianchangbang”. The aim of this study was to investigate differences in the composition and therapeutic mechanism of the unprocessed lateral root of Aconitum carmichaelii (ULRA) and its processed product (YF). Methods: Ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry and orthogonal partial least squares discriminant analysis method were used to determine and screen the main components of ULRA and YF. Changes in the histological structure and morphology of gonads in rats were observed using hematoxylin-eosin. Enzyme-linked immunosorbent assay was used to determine the contents of serum cyclic adenosine monophosphate and cyclic guanosine monophosphate in YDS rats treated with ULRA and YF. Tandem mass tag proteomics analysis was used to identify the differentially expressed proteins in YDS rats treated with ULRA and YF. Results: Both ULRA and YF exerted certain therapeutic effects on rats with YDS. They improved the gonadal morphology and increased the contents of serum cyclic adenosine monophosphate and cyclic guanosine monophosphate. After processing of ULRA into YF, the content of C19-diester-diterpenoid alkaloids decreased (converted into C19-monoester-diterpenoid alkaloids and C19-alkylol amine-diterpenoid alkaloids), whereas that of C20-diterpene alkaloids increased. Proteomics analysis showed that cytochrome P450 and aldehyde oxidase 3 (AOX3) were downregulated, whereas cathepsin G (CTSG) was upregulated in rats with YDS. Treatment with ULRA mainly downregulated the expression of α-actinin, fast skeletal troponin, creatine kinase, and myosin. Treatment with YF mainly upregulated the expression of mitochondrial ribosomal protein and mitochondrial inner membrane protein. Conclusion: ULRA and YF exerted good therapeutic effects on YDS; the main difference in components between these preparations was in C19-diterpenoid alkaloids. ULRA mainly acts on the muscle contraction-related proteins and is closely related to inflammation and myocardial injury. YF mainly acts on the mitochondrial proteins and is closely related to adenosine triphosphate energy metabolism.

Asymmetric Total Synthesis of Hetidine-Type C20-Diterpenoid Alkaloids: (+)-Talassimidine and (+)-Talassamine.

Here, we report the first asymmetric total synthesis of (+)-talassimidine and (+)-talassamine, two hetidine-type C20-diterpenoid alkaloids. A highly regio- and diastereoselective 1,3-dipolar cycloaddition of an azomethine ylide yielded a chiral tetracyclic intermediate in high enantiopurity, thus providing the structural basis for asymmetric assembly of the hexacyclic hetidine skeleton. In this key step, the introduction of a single chiral center induces four new continuous chiral centers. Another key transformation is the dearomative cyclopropanation of the benzene ring and subsequent SN2-like ring opening of the resultant cyclopropane ring with water as a nucleophile, which not only establishes the B ring but also precisely installs the difficult-to-achieve equatorial C7-OH group.

A comprehensive review of phytochemistry, pharmacology and toxicology of the genus Aconitum L.

The genus Aconitum (family—Ranunculaceae) accounts for approximately 400 species worldwide, of which some are considered medicinally very relevant. Many species have been reported to possess significant pharmacological properties and high therapeutic index for curing various diseases. Traditionally, Aconitum species have been used for the treatment of different human ailments, especially, neuronal disorders, pain and inflammation, kidney related disorders, rheumatism, diabetes, hysteria and cardiac depression. These medicinal properties have been attributed to various classes of secondary metabolites found in different Aconitum species. Among them, C19 and C20-diterpenoid alkaloids are the most dynamic group of compounds, comprising of more than 450 alkaloids in various species across the genus. However, further detailed phytochemical investigations of Aconitum species could provide new therapeutic natural products of Aconitum source that could be employed in health and medicine. The present study aims to frame a well structured portfolio to provide contemporary insights of the genus Aconitum. The retrospection of all the available information on Aconitum associated with its various attributes was carried out by searching different electronic databases viz. Elsevier, PubMed, Web of Science, Scifinder, ScienceDirect, ResearchGate, Google Scholar, Bio One, PLOS. The review summarizes the findings on traditional uses, phytochemistry, and pharmacology of various species of the genus. The toxicology and safety of Aconitum species for human consumption as herbal drugs has also been discussed.

C19-diterpenoid alkaloids from the rhizomes of Aconitum pendulum

Six new C19-aconitine-type diterpenoid alkaloids, pendulumines A-F (1–6), together with six known ones (7–12), were isolated from the rhizomes of Aconitum pendulum. Their structures were elucidated using extensive spectroscopic data analysis, including 1D and 2D NMR, MS, and single-crystal X-ray diffraction analysis. The isolates were also tested for their analgesic activity based on the thermal avoidance response of the roundworm Pirstionchus pacificus, and 9 showed significant biological activity with an EC50 value of 0.08 ± 0.02 mg.mL−1.

Alkaloids of Delphinium grandiflorum and their implication to H2O2-induced cardiomyocytes injury

Three new diterpenoid alkaloids (1–3), and eight known alkaloids (4–11) were isolated from the aerial parts of Delphinium grandiflorum. Grandifline A (1) represents an unprecedented diterpenoid alkaloid ring system featuring a C-7NC17 hemiaminal moiety and a lactone fragment through the linkage of C-17OC19 unit. And we named this newly-discovered class of rearranged C19-diterpenoid alkaloid scaffold as grandiflodines (B-12). Grandifline B (2) is the first naturally-occurring 7,17-secolycoctonine diterpenoid alkaloid with a C-7OC17 unit forming a hemiacetal. Their structures were elucidated via spectroscopic data and single-crystal X-ray diffraction analysis. The protective effects of compounds 1–11 on H2O2-induced cardiomyocytes injury were assayed. And compounds 6 and 10 showed significant protective effects, with IC50 values of 1.881 ± 0.680 μM and 1.904 ± 0.750 μM, respectively. Further, compound 6 could reduce oxidative damage by inhibiting cell death via the AMPK/AKT/mTOR signaling pathway in H2O2-induced H9C2 cells.

A new route to BCD tricyclic fragment of C19-diterpenoid alkaloids via intramolecular Pauson-Khand reaction followed by anionic 1,2-migration rearrangement

A robust synthetic approach for the rapid assembly of the bridged tricyclic BCD ring system of C19-diterpenoid alkaloids bearing a characteristic hydroxy group on ring C has been developed. The synthesis features an efficient intramolecular Pauson-Khand reaction and an exclusive anionic 1,2-migration rearrangement to generate the unique bicyclo[3.2.1]octane moiety of the CD-ring on the seven-membered B-ring.

Isolation, Structure Elucidation, Semi-Synthesis, and Structural Modification of C19-Diterpenoid Alkaloids from Aconitum apetalum and Their Neuroprotective Activities.

Five new aconitine-type C19-diterpenoid alkaloids, apetalrines A-E (1-5), were isolated from Aconitum apetalum. Their structures were determined by analysis of 1D and 2D NMR, IR, and HRESIMS data. Semisynthesis of apetalrine B (2) from its parent compound aconorine was achieved to confirm the structure proposed. Twenty derivatives of 2 (11a-11l, 12a, 12b, 12d, 12e, 12j, 12k, 12m, 12n) were synthesized via a unified approach relying on simple coupling reactions. The evaluation of neuroprotective effects of compounds (1-5, 11b, 11c, 11f-11i, 12a, 12b, 12d, 12e, 12k, 12m, 12n) with low cytotoxicity revealed compound 2 to exhibit good neuroprotective effects in H2O2-treated SH-SY5Y cells at a concentration of 50 μM. A series of studies using flow cytometry, staining, and Western blotting on 2 indicated that its neuroprotective effects may arise from inhibiting cell apoptosis.

Bulleyaconitine A Inhibits Morphine-Induced Withdrawal Symptoms, Conditioned Place Preference, and Locomotor Sensitization Via Microglial Dynorphin A Expression.

Bulleyaconitine A (BAA), a C19-diterpenoid alkaloid, has been prescribed as a nonnarcotic analgesic to treat chronic pain over four decades in China. The present study investigated its inhibition in morphine-induced withdrawal symptoms, conditioned place preference (CPP) and locomotor sensitization, and then explored the underlying mechanisms of actions. Multiple daily injections of morphine but not BAA up to 300 μg/kg/day into mice evoked naloxone-induced withdrawal symptoms (i.e., shakes, jumps, genital licks, fecal excretion and body weight loss), CPP expression, and locomotor sensitization. Single subcutaneous BAA injection (30–300 μg/kg) dose-dependently and completely attenuated morphine-induced withdrawal symptoms, with ED50 values of 74.4 and 105.8 μg/kg in shakes and body weight loss, respectively. Subcutaneous BAA (300 μg/kg) also totally alleviated morphine-induced CPP acquisition and expression and locomotor sensitization. Furthermore, subcutaneous BAA injection also specifically stimulated dynorphin A expression in microglia but not astrocytes or neurons in nucleus accumbens (NAc) and hippocampal, measured for gene and protein expression and double immunofluorescence staining. In addition, subcutaneous BAA-inhibited morphine-induced withdrawal symptoms and CPP expression were totally blocked by the microglial metabolic inhibitor minocycline, dynorphin A antiserum, or specific KOR antagonist GNTI, given intracerebroventricularly. These results, for the first time, illustrate that BAA attenuates morphine-induced withdrawal symptoms, CPP expression, and locomotor sensitization by stimulation of microglial dynorphin A expression in the brain, suggesting that BAA may be a potential candidate for treatment of opioids-induced physical dependence and addiction.