11-Hydroxypolyneuridine

11-Hydroxypolyneuridine at a Glance

11-Hydroxypolyneuridine is a monoterpenoid indole alkaloid described in a single paper. In 2012 a Turkish group reported it as a new compound isolated from Vinca major subsp. major — greater periwinkle — alongside the first alkaloid survey of both V. major and V. minor growing in Turkey ^{1Reference 1Bahadori F et al. · 2012Indole alkaloids from Vinca major and V. minor growing in TurkeyView study →}.

That paper is the whole record. A PubMed search for hydroxypolyneuridine returns one result — the isolation paper itself — and Europe PMC returns the same single hit (both checked 31 July 2026). The compound has no PubChem CID and no PubChem substance record, no ChEBI entry and no Wikidata item, which means no published formula, no CAS number and no InChIKey are attached to the name in any public chemical database (all checked 31 July 2026). It has never been tested in any assay.

What it does have is a well-characterised parent. Strip the hydroxyl and you get polyneuridine, a sarpagan-type alkaloid whose aldehyde form sits at a famous branch point in plant alkaloid biosynthesis — the step that produces the antiarrhythmic alkaloid ajmaline ^{4,5Reference 4Pfitzner A · 1983Characterization of polyneuridine aldehyde esterase, a key enzyme in the biosynthesis of sarpagine/ajmaline type alkaloidsView study →Reference 5Dogru E et al. · 2000The gene encoding polyneuridine aldehyde esterase of monoterpenoid indole alkaloid biosynthesis in plants is an ortholog of the alpha/beta hydrolase super familyView study →}. That enzymology is genuinely well studied, and it is polyneuridine’s, not this molecule’s. This page keeps the two separated, because the whole risk with an obscure hydroxylated analogue is that its relative’s literature quietly becomes its own.

Identity & Structure

What the name asserts. The compound is named as polyneuridine bearing an extra hydroxyl at position 11. Public chemical records for the parent give polyneuridine as C₂₁H₂₄N₂O₃ (MW 352.4), systematically methyl (16R)-17-hydroxysarpagan-16-carboxylate ^{3Reference 3National Center for Biotechnology Inform · 2026PubChem Compound Summary for CID 5374154, methyl (16R)-17-hydroxysarpagan-16-carboxylate (polyneuridine); accessed 31 July 2026View study →} — that is, the sarpagan cage carrying a carbomethoxy group at C-16 and a hydroxymethyl at C-17.

Where C-11 sits. Monoterpenoid indole alkaloids are numbered by the uniform biogenetic scheme of Le Men and Taylor (1965) ^{2Reference 2Le Men L · 1965A uniform numbering system for indole alkaloidsView study →}, in which C-9 to C-12 are the four carbons of the indole benzene ring. Relatives named on that convention bear out the reading: 11-hydroxytabersonine and 11-methoxyakuammicine both carry their substituent on the aromatic ring in their deposited structures ^{3Reference 3National Center for Biotechnology Inform · 2026PubChem Compound Summary for CID 5374154, methyl (16R)-17-hydroxysarpagan-16-carboxylate (polyneuridine); accessed 31 July 2026View study →}. On that basis 11-hydroxypolyneuridine should be polyneuridine with an aromatic (phenolic) hydroxyl on the indole benzo ring — a common, and chemically minor-looking, decoration in this family.

What could not be checked. The primary paper’s characterisation data — the NMR assignments, HRMS and the argument that placed the hydroxyl at C-11 rather than C-9, C-10 or C-12 — sit behind a paywall that could not be opened; the abstract does not carry them. Arithmetic implies a hydroxylated polyneuridine would be C₂₁H₂₄N₂O₄, but that is arithmetic, not a reported measurement, and no formula, CAS number or InChIKey for this compound could be located in any public database. Nothing further about its stereochemistry, physical properties or spectroscopic behaviour is stated here, because nothing further is available.

Its Place in the Sarpagine–Ajmaline Route

This is the reason the parent compound has a literature at all, and it is worth setting out precisely — including where it stops applying to the molecule described here.

The pathway. In Rauvolfia serpentina and its Apocynaceae relatives, the intermediate geissoschizine is cyclised by cytochrome-P450 sarpagan bridge enzymes, which forge the C5–C16 bond of the sarpagan cage and deliver polyneuridine aldehyde (predominantly the 16R isomer) ^{8Reference 8Mann SGA et al. · 2025Stereochemical insights into sarpagan and akuammiline alkaloid biosynthesisView study →}. That aldehyde is then handed to polyneuridine aldehyde esterase (PNAE), which hydrolyses the methyl ester and, with loss of carbon dioxide, converts the monoterpenoid C10 unit into a C9 unit, giving the labile alkaloid 16-epi-vellosimine ^{4,7Reference 4Pfitzner A · 1983Characterization of polyneuridine aldehyde esterase, a key enzyme in the biosynthesis of sarpagine/ajmaline type alkaloidsView study →Reference 7Yang L et al. · 2009Structural basis and enzymatic mechanism of the biosynthesis of C9- from C10-monoterpenoid indole alkaloidsView study →}. 16-Epi-vellosimine is the branch point: from it the routes to sarpagan- and ajmalan-type alkaloids diverge, and it is the immediate precursor of the ajmalane skeleton ^{4,5Reference 4Pfitzner A · 1983Characterization of polyneuridine aldehyde esterase, a key enzyme in the biosynthesis of sarpagine/ajmaline type alkaloidsView study →Reference 5Dogru E et al. · 2000The gene encoding polyneuridine aldehyde esterase of monoterpenoid indole alkaloid biosynthesis in plants is an ortholog of the alpha/beta hydrolase super familyView study →}.

Why PNAE is well studied. Ajmaline biosynthesis runs through more than ten specific enzymes, and PNAE occupies a central position in the sequence ^{5Reference 5Dogru E et al. · 2000The gene encoding polyneuridine aldehyde esterase of monoterpenoid indole alkaloid biosynthesis in plants is an ortholog of the alpha/beta hydrolase super familyView study →}. It was purified from R. serpentina cell suspension cultures in 1983 ^{4Reference 4Pfitzner A · 1983Characterization of polyneuridine aldehyde esterase, a key enzyme in the biosynthesis of sarpagine/ajmaline type alkaloidsView study →}, its cDNA cloned in 2000 — revealing an α/β-hydrolase-superfamily protein of extraordinary substrate specificity ^{5Reference 5Dogru E et al. · 2000The gene encoding polyneuridine aldehyde esterase of monoterpenoid indole alkaloid biosynthesis in plants is an ortholog of the alpha/beta hydrolase super familyView study →} — its catalytic triad pinned down by modelling and site-directed mutagenesis in 2002 ^{6Reference 6Mattern-Dogru E et al. · 2002Potential active-site residues in polyneuridine aldehyde esterase, a central enzyme of indole alkaloid biosynthesis, by modelling and site-directed mutagenesisView study →}, and its three-dimensional structure solved in 2009, confirming a serine esterase with an S87–D216–H244 triad ^{7Reference 7Yang L et al. · 2009Structural basis and enzymatic mechanism of the biosynthesis of C9- from C10-monoterpenoid indole alkaloidsView study →}. Few plant alkaloid enzymes are characterised in that much detail.

Where polyneuridine itself fits. Polyneuridine is the C-17 alcohol corresponding to polyneuridine aldehyde — reduction of the authentic aldehyde yields polyneuridine as a single product ^{8Reference 8Mann SGA et al. · 2025Stereochemical insights into sarpagan and akuammiline alkaloid biosynthesisView study →} — so it is best read as a reduced, off-the-esterase shunt product rather than an obligatory intermediate. Its C-16 epimer is akuammidine, the 16S member of the same pair; the 2025 study that resolved this stereochemistry also characterised a new akuammidine aldehyde reductase among the downstream tailoring enzymes that shuffle C-16 configuration across species ^{8Reference 8Mann SGA et al. · 2025Stereochemical insights into sarpagan and akuammiline alkaloid biosynthesisView study →}.

The boundary. None of the above has been demonstrated for 11-hydroxypolyneuridine. No enzyme has been shown to make it, no aromatic hydroxylase has been assigned to it, and it has not been detected as an intermediate or a shunt product in any pathway study. Its placement in this family is by name and skeleton, which is a reasonable structural inference and not a biosynthetic finding. PNAE’s substrate is polyneuridine aldehyde; this molecule is a hydroxylated analogue of the alcohol, one reduction step and one hydroxyl removed from the characterised step.

Its Place in the Vinca major Alkaloid Pool

Vinca major is a chemically busy but lightly studied plant: 32 indexed papers name the species at all (PubMed, checked 31 July 2026), and most are phytochemistry rather than pharmacology.

Its alkaloid pool is heterogeneous and structurally mixed. A 1982 analysis of V. major cv. Variegata leaves isolated seven alkaloids — reserpinine, majdine, akuammicine, strictosidine lactam, pseudoakuammigine, akuammine and a compound tentatively assigned as 10-hydroxycathofoline — and found no difference in profile between the yellowish and green sections of the variegated leaf ^{10Reference 10Balsevich J et al. · 1982Alkaloids of Vinca major cvView study →}. Later work added three new monoterpenoid indole alkaloids of the dihydrovinorine series from the whole plant ^{11Reference 11Zhang ZJ et al. · 2016Three new monoterpenoid indole alkaloids from Vinca majorView study →}, three new pyridine-type alkaloids from Pakistani material ^{12Reference 12Wei X et al. · 2017Three new pyridine alkaloids from Vinca major cultivated in PakistanView study →}, and, from the non-alkaloid fraction, a new iridoid glycoside with moderate DPPH-scavenging activity ^{13Reference 13Cheng GG et al. · 2016Non-alkaloid constituents of Vinca majorView study →}. The 2012 Turkish survey that named 11-hydroxypolyneuridine belongs to this same sequence of one-off isolations ^{1Reference 1Bahadori F et al. · 2012Indole alkaloids from Vinca major and V. minor growing in TurkeyView study →}.

The sarpagine–ajmaline family is already represented in this plant. Vincamajine, a V. major constituent, is grouped with the sarpagine–ajmaline–koumine alkaloids in the synthetic literature, alongside akuammidine, vincamedine, vincarine and quebrachidine ^{9Reference 9Chen W et al. · 2022Structure units oriented approach towards collective synthesis of sarpagine-ajmaline-koumine type alkaloidsView study →}. A sarpagan-type alkaloid turning up in V. major is therefore chemically unsurprising — which is context, not evidence.

Not the chemotherapy alkaloids. Vinblastine and vincristine are bisindole alkaloids from Catharanthus roseus (Madagascar periwinkle) — a different genus, a different structural class, and a cytotoxic chemotherapy record that has nothing to do with Vinca major or with this molecule. Nor does V. minor’s vincamine story transfer. Keep the three plants separate.

What It's Used For

There is no pharmacology to report. 11-Hydroxypolyneuridine has never been tested for any biological activity — no receptor binding, no enzyme assay, no cell-line screen, no animal work, no human exposure. That absence is the finding, not a shortfall in searching — the searches, counts and dates are given below and in the takeaways.

Mechanisms

None characterised. No target, receptor, enzyme, pathway or mode of action has been reported for 11-hydroxypolyneuridine.

Reasoning from the parent is not available either. Polyneuridine itself has almost no pharmacology: the one activity figure attached to the name comes from a Podophyllum hexandrum rhizome extract study, where a GC-MS-identified component labelled polyneuridine showed DPPH scavenging with an IC₅₀ of 13.37 µM and a FRAP value of 2404 µM, stronger than the ascorbic-acid control ^{18Reference 18Li M et al. · 2012Biochemical composition and antioxidant capacity of extracts from Podophyllum hexandrum rhizomeView study →} — a component-level antioxidant measurement inside an extract study, not a mechanism, and reported for polyneuridine in a plant unrelated to Vinca. In Rhazya stricta, where three co-isolated alkaloids were cytotoxic, polyneuridine was not among them ^{17Reference 17Mukhopadhyay S et al. · 1981Anticancer indole alkaloids of Rhazya strictaView study →}. Neither observation says anything about the 11-hydroxy analogue.

Pharmacokinetics

No data. Absorption, distribution, metabolism, bioavailability, half-life and metabolites are all unstudied — as they must be for a compound with no reference standard and no administration to any organism.

Clinical Trials

None, and none preclinical. The compound has never entered a trial of any kind and has no preclinical programme behind it.

Last checked: July 2026.

Isolate vs. Plant Studies

The usual isolate-versus-plant question has an unusually clean answer here: there are no isolate studies at all, and the plant-level studies do not resolve to this molecule.

11-Hydroxypolyneuridine was isolated in 2012 — purified to the point of structural assignment — but never assayed. The bioactivity in that same paper was measured on the V. major and V. minor alkaloid extracts: high lipid-peroxidation inhibition, high DPPH scavenging, very strong anticholinesterase activity ^{1Reference 1Bahadori F et al. · 2012Indole alkaloids from Vinca major and V. minor growing in TurkeyView study →}. Those are whole-fraction in-vitro results. A crude alkaloid extract of V. major contains reserpinine, majdine, akuammicine, akuammine, pseudoakuammigine and others ^{10Reference 10Balsevich J et al. · 1982Alkaloids of Vinca major cvView study →}, any of which could carry the signal; no bioassay-guided fractionation has been published that would apportion it.

The wider V. major literature does not help. The species’ cytotoxicity screens are compound-level and largely negative — the three new pyridine alkaloids were inactive against glioma, glioblastoma and lung cancer lines at 20 µg/mL ^{12Reference 12Wei X et al. · 2017Three new pyridine alkaloids from Vinca major cultivated in PakistanView study →} — and the plant has no human data of its own ^{10,11,12,13Reference 10Balsevich J et al. · 1982Alkaloids of Vinca major cvView study →Reference 11Zhang ZJ et al. · 2016Three new monoterpenoid indole alkaloids from Vinca majorView study →Reference 12Wei X et al. · 2017Three new pyridine alkaloids from Vinca major cultivated in PakistanView study →Reference 13Cheng GG et al. · 2016Non-alkaloid constituents of Vinca majorView study →}. So the honest statement is: zero isolate evidence, and plant-level evidence that cannot be attributed to this constituent.

Prevalence in Nature

Known from one plant, one report, and no number.

The only reported source of 11-hydroxypolyneuridine is Vinca major subsp. major collected in Turkey ^{1Reference 1Bahadori F et al. · 2012Indole alkaloids from Vinca major and V. minor growing in TurkeyView study →}. The abstract states neither the plant part nor the yield, and the full text was not accessible, so no concentration figures are given — not a percentage, not a mg/g, not a share of the alkaloid fraction. No other study, in Vinca or elsewhere, reports detecting the compound.

The parent is more widely distributed, which is worth recording as context and not as occurrence data for this molecule. Polyneuridine has been reported from Rhazya stricta leaves and roots (its first report from that species) ^{17Reference 17Mukhopadhyay S et al. · 1981Anticancer indole alkaloids of Rhazya strictaView study →}, as the N-oxide from the roots of Ochrosia acuminata ^{16Reference 16Salim AA et al. · 2004New indole alkaloids from the roots of Ochrosia acuminataView study →}, and among the alkaloids identified by LC-MS/MS and GC-MS in the aboveground organs of Vinca rosea L. — a synonym of Catharanthus roseus, the Madagascar periwinkle, and therefore a different genus from the plant here ^{19Reference 19Vachnadze V et al. · 2021Vachnadze V, Vachnadze N, Bakuridze A, Jokhadze M, Mshvildadze V (2021). [Study of the cytotoxic activity of indole alkaloids from the aboveground organs of Vinca rosea L. introduced in Western Georgia]. Georgian Medical News (320):172–178. https://pubmed.ncbi.nlm.nih.gov/34897067/View study →}. A GC-MS-based identification of polyneuridine has also been reported from Podophyllum hexandrum rhizome extract ^{18Reference 18Li M et al. · 2012Biochemical composition and antioxidant capacity of extracts from Podophyllum hexandrum rhizomeView study →}, an assignment made on chromatographic grounds without isolation. All of these are the parent, not the 11-hydroxy compound.

Discovery & Synthesis

First and only isolation (2012). Bahadori, Topçu, Boğa, Türkekul, Kolak and Kartal reported 11-hydroxypolyneuridine as a new indole alkaloid from Vinca major subsp. major L. in Natural Product Communications, in the first study of the alkaloids of both Vinca species growing in Turkey ^{1Reference 1Bahadori F et al. · 2012Indole alkaloids from Vinca major and V. minor growing in TurkeyView study →}. The name is straightforwardly descriptive: the parent alkaloid plus a hydroxy locant. Whether an earlier, differently-named report of the same structure exists in the older Vinca literature could not be determined without the full text.

Total synthesis. None reported for 11-hydroxypolyneuridine. The parent has been made twice by the same group: Yin, Ma, Rivas and Cook reported the first enantiospecific total synthesis of (+)-polyneuridine and (+)-polyneuridine aldehyde, together with 16-epi-vellosimine and macusine A, in 2007 ^{14Reference 14Yin W et al. · 2007First enantiospecific total synthesis of the important biogenetic intermediates, (+)-polyneuridine and (+)-polyneuridine aldehyde, as well as 16-epi-vellosimine and macusine AView study →}, and published the full account — starting from D-(+)-tryptophan methyl ester via an asymmetric Pictet–Spengler reaction, Dieckmann cyclisation and a stereocontrolled intramolecular cross-coupling — in 2010 ^{15Reference 15Yin W et al. · 2010Enantiospecific total synthesis of the important biogenetic intermediates along the ajmaline pathway, (+)-polyneuridine and (+)-polyneuridine aldehyde, as well as 16-epivellosimine and macusine AView study →}. The corynanthe–sarpagine–ajmaline family has since been addressed by unified biomimetic strategies ^{20Reference 20Sun YK et al. · 2025Unified chemical synthesis of corynanthe-sarpagine-ajmaline type monoterpene indole alkaloids: a biomimetic approachView study →} and by collective asymmetric routes that delivered akuammidine, vincamajine, quebrachidine and eleven other alkaloids ^{9Reference 9Chen W et al. · 2022Structure units oriented approach towards collective synthesis of sarpagine-ajmaline-koumine type alkaloidsView study →}. A route to the 11-hydroxy analogue would plausibly branch from that chemistry, but none has been published.

Manufacture today. None. The compound is not produced, not sold, and not available as an analytical reference standard — which is the practical reason it has never appeared in a quantitative method or a screening library.

Patents: not yet researched.

Toxicity & Safety

Toxicity is not established, and cannot be from the existing record. There is no toxicology, no genotoxicity assay, no repeat-dose study, no reproductive data and no human exposure data for 11-hydroxypolyneuridine. The unknown grading reflects a complete absence of data, not a finding of safety.

Two cautions follow, pointing in opposite directions.

Do not read safety from silence. Nothing here says the compound is harmless. It is an indole alkaloid from a plant this database flags as moderately toxic, and it has simply never been assessed.

Do not read the herb’s risks onto it either. Greater periwinkle carries real cautions — its alkaloid content is unstandardised, prolonged therapeutic use is discouraged, and the herb page sets out the contraindications, including in pregnancy. Those belong to the periwinkle herb page, where intake is actually decided. Attributing them to a trace constituent that has never been dosed would be as unfounded as attributing benefits to it. The chemotherapy toxicity of vinblastine and vincristine is a different genus’s problem entirely and does not apply here.

Safety at a Glance

❔ Toxicity unknown

• Toxicity genuinely unknown. No toxicology, genotoxicity, reproductive or human-exposure data exist for this molecule. Absence of reported harm is not evidence of safety.
• No characterised, purchasable isolate. No public database record, no CAS number, no reference standard — nothing to test and nothing to standardise. Any product claim naming this compound is unverifiable.
• The herb’s own cautions are real and belong to the herb. Unstandardised alkaloid content, discouraged long-term use and the pregnancy contraindication are set out on the periwinkle herb page; they are not transferred to — or excused by — this constituent.

Dosage

There is no dose, and no basis for one. 11-Hydroxypolyneuridine has never been administered to a cell line, an animal or a person, has never been quantified in any preparation, and is not sold in any form.

Periwinkle’s own dosing discussion — and the isolated-alkaloid dosing that surrounds vincamine and vinpocetine, which concern a different molecule from a different species — belongs on those pages, not here. Nothing here is dosing guidance.

References

1. Bahadori F, Topçu G, Boğa M, Türkekul A, Kolak U, Kartal M (2012). Indole alkaloids from Vinca major and V. minor growing in Turkey. Natural Product Communications 7(6):731–734. https://pubmed.ncbi.nlm.nih.gov/22816294/
2. Le Men L, Taylor WI (1965). A uniform numbering system for indole alkaloids. Experientia 21(9):508–510. https://pubmed.ncbi.nlm.nih.gov/5872609/
3. National Center for Biotechnology Information. PubChem Compound Summary for CID 5374154, methyl (16R)-17-hydroxysarpagan-16-carboxylate (polyneuridine); accessed 31 July 2026. https://pubchem.ncbi.nlm.nih.gov/compound/5374154
4. Pfitzner A, Stöckigt J (1983). Characterization of polyneuridine aldehyde esterase, a key enzyme in the biosynthesis of sarpagine/ajmaline type alkaloids. Planta Medica 48(8):221–227. https://pubmed.ncbi.nlm.nih.gov/17404987/
5. Dogru E, Warzecha H, Seibel F, Haebel S, Lottspeich F, Stöckigt J (2000). The gene encoding polyneuridine aldehyde esterase of monoterpenoid indole alkaloid biosynthesis in plants is an ortholog of the alpha/beta hydrolase super family. European Journal of Biochemistry 267(5):1397–1406. https://pubmed.ncbi.nlm.nih.gov/10691977/
6. Mattern-Dogru E, Ma X, Hartmann J, Decker H, Stöckigt J (2002). Potential active-site residues in polyneuridine aldehyde esterase, a central enzyme of indole alkaloid biosynthesis, by modelling and site-directed mutagenesis. European Journal of Biochemistry 269(12):2889–2896. https://pubmed.ncbi.nlm.nih.gov/12071952/
7. Yang L, Hill M, Wang M, Panjikar S, Stöckigt J (2009). Structural basis and enzymatic mechanism of the biosynthesis of C9- from C10-monoterpenoid indole alkaloids. Angewandte Chemie International Edition 48(28):5211–5213. https://pubmed.ncbi.nlm.nih.gov/19496101/
8. Mann SGA, Paz-Galeano M, Shahsavarani M, Perley JO, Guo J, Garza-Garcia JJO, Qu Y (2025). Stereochemical insights into sarpagan and akuammiline alkaloid biosynthesis. New Phytologist 247(3):1335–1351. https://pubmed.ncbi.nlm.nih.gov/40458973/
9. Chen W, Ma Y, He W, Wu Y, Huang Y, Zhang Y, Tian H, Wei K, Yang X, Zhang H (2022). Structure units oriented approach towards collective synthesis of sarpagine-ajmaline-koumine type alkaloids. Nature Communications 13:908. https://pubmed.ncbi.nlm.nih.gov/35177620/
10. Balsevich J, Constabel F, Kurz WG (1982). Alkaloids of Vinca major cv. Variegata. Planta Medica 44(2):91–93. https://pubmed.ncbi.nlm.nih.gov/17402086/
11. Zhang ZJ, Du RN, He J, Wu XD, Li Y, Li RT, Zhao QS (2016). Three new monoterpenoid indole alkaloids from Vinca major. Journal of Asian Natural Products Research 18(4):328–333. https://pubmed.ncbi.nlm.nih.gov/26700398/
12. Wei X, Khan A, Song D, Dai Z, Liu YP, Yu HF, Wang B, Zhu PF, Ding CF, Zhao XD, Wang YF, Luo XD (2017). Three new pyridine alkaloids from Vinca major cultivated in Pakistan. Natural Products and Bioprospecting 7(4):323–327. https://pubmed.ncbi.nlm.nih.gov/28620872/
13. Cheng GG, Zhao HY, Liu L, Zhao YL, Song CW, Gu J, Sun WB, Liu YP, Luo XD (2016). Non-alkaloid constituents of Vinca major. Chinese Journal of Natural Medicines 14(1):56–60. https://pubmed.ncbi.nlm.nih.gov/26850347/
14. Yin W, Ma J, Rivas FM, Cook JM (2007). First enantiospecific total synthesis of the important biogenetic intermediates, (+)-polyneuridine and (+)-polyneuridine aldehyde, as well as 16-epi-vellosimine and macusine A. Organic Letters 9(2):295–298. https://pubmed.ncbi.nlm.nih.gov/17217288/
15. Yin W, Kabir MS, Wang Z, Rallapalli SK, Ma J, Cook JM (2010). Enantiospecific total synthesis of the important biogenetic intermediates along the ajmaline pathway, (+)-polyneuridine and (+)-polyneuridine aldehyde, as well as 16-epivellosimine and macusine A. The Journal of Organic Chemistry 75(10):3339–3349. https://pubmed.ncbi.nlm.nih.gov/20392128/
16. Salim AA, Garson MJ, Craik DJ (2004). New indole alkaloids from the roots of Ochrosia acuminata. Journal of Natural Products 67(10):1719–1721. https://pubmed.ncbi.nlm.nih.gov/15497947/
17. Mukhopadhyay S, Handy GA, Funayama S, Cordell GA (1981). Anticancer indole alkaloids of Rhazya stricta. Journal of Natural Products 44(6):696–700. https://pubmed.ncbi.nlm.nih.gov/7334384/
18. Li M, Zhou L, Yang D, Li T, Li W (2012). Biochemical composition and antioxidant capacity of extracts from Podophyllum hexandrum rhizome. BMC Complementary and Alternative Medicine 12:263. https://pubmed.ncbi.nlm.nih.gov/23259745/
19. Vachnadze V, Vachnadze N, Bakuridze A, Jokhadze M, Mshvildadze V (2021). [Study of the cytotoxic activity of indole alkaloids from the aboveground organs of Vinca rosea L. introduced in Western Georgia]. Georgian Medical News (320):172–178. https://pubmed.ncbi.nlm.nih.gov/34897067/
20. Sun YK, Guo XF, Bu Y, Qiao JB, Zhao YM (2025). Unified chemical synthesis of corynanthe-sarpagine-ajmaline type monoterpene indole alkaloids: a biomimetic approach. JACS Au 5(10):4956–4962. https://pubmed.ncbi.nlm.nih.gov/41169574/

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