Cryptolepis

Cryptolepis originates from Africa, where it was primarily used to treat malaria, amoebic dysentery, and both urinary and respiratory infection.

The herb’s success with malaria patients is what made the plant so popular today, and there is now large plots of land dedicated to its cultivation to meet the demand for the herb within Africa, as well as elsewhere in the world.

A closely related but separate species — Cryptolepis buchanii — grows throughout Indonesia, Thailand, China, India, and Nepal. Its alkaloid profile differs from the studied West African species, so the uses below belong to C. buchanii and should not be attributed to C. sanguinolenta.

This species was used in Thailand for treating systemic inflammation, arthritis, and muscle pain.

In India, this species was used to treat diarrhea, bacterial infection, ulcers, and for treating rickets in children.

This is the herb’s traditional core use and its best-evidenced one. In vitro, cryptolepine and related alkaloids strongly inhibit both chloroquine-sensitive and chloroquine-resistant Plasmodium falciparum, and cryptolepine hydrochloride was chemosuppressive in P. berghei-infected mice ^{2Reference 2Cimanga et al. · 1997In vitroIn vitro and in vivo antiplasmodial activity of cryptolepine and related alkaloids from Cryptolepis sanguinolenta — in vitro and animal in vivoView study →}; activity is retained across leaf and root alkaloid fractions ^{3Reference 3Paulo et al. · 2000In vitroAntiplasmodial activity of Cryptolepis sanguinolenta alkaloids from leaves and roots — in vitroView study →}. Cryptolepine also acts synergistically with artemisinin derivatives against P. falciparum in vitro and in a rodent model ^{4Reference 4Forkuo et al. · 2016In vitroSynergistic anti-malarial action of cryptolepine and artemisinins — in vitro and animal modelView study →}. The one human study — an open-label, uncontrolled trial (n=44) of a standardised root tea-bag (2.5 g equivalent, three times daily for 5 days) in acute uncomplicated falciparum malaria — cleared parasitaemia in 50% of patients by 72 hours and all by day 7, with fever, chills, nausea and vomiting resolving by day 3 and a 93.5% overall cure rate (two late recrudescences on days 21 and 28); no laboratory toxicity was seen over the trial ^{1Reference 1Bugyei et al. · 2010Clinical trialClinical efficacy of a tea-bag formulation of Cryptolepis sanguinolenta root in the treatment of acute uncomplicated falciparum malaria — clinical trialView study →}.

Gap: the human evidence is a single small open-label trial with no comparator and short follow-up; there is no randomised controlled trial, and the tea’s efficacy against severe or non-falciparum malaria is untested.

Cryptolepis is the herb most West African practitioners reach for as a systemic antibacterial, and the in vitro record is broad. Ethanolic and solvent fractions of the root inhibit a wide panel of Gram-positive and Gram-negative organisms; in one fractionation study the chloroform fraction inhibited 100% of test organisms and was the only fraction that was bactericidal rather than merely bacteriostatic, while the water fraction inhibited ~75–88% of strains ^{7Reference 7Mills-Robertson et al. · 2012In vitroIn vitro antimicrobial activity of ethanolic fractions of Cryptolepis sanguinolenta — in vitroView study →}. Isolated alkaloids reproduce the effect: cryptolepine and neocryptolepine are active against enteric and diarrhoeal pathogens including Shigella, Salmonella, Vibrio cholerae and Campylobacter ^{8,9Reference 8Paulo et al. · 1994In vitroIn vitro antibacterial screening of Cryptolepis sanguinolenta alkaloids — in vitroView study →Reference 9Paulo et al. · 1994In vitroCryptolepis sanguinolenta activity against diarrhoeal bacteria — in vitroView study →}, and cryptolepine is directly bactericidal against Staphylococcus aureus, killing via membrane disruption and DNA intercalation ^{10Reference 10Sawer et al. · 2005In vitroThe killing effect of cryptolepine on Staphylococcus aureus — in vitroView study →}. Neocryptolepine, biscryptolepine and cryptoquindoline add further activity, with neocryptolepine reported as more bacteriostatic than bactericidal ^{11Reference 11Cimanga et al. · 1998In vitroAntibacterial and antifungal activities of neocryptolepine, biscryptolepine and cryptoquindoline, alkaloids isolated from Cryptolepis sanguinolenta — in vitroView study →}.

Gap: all human-relevant data are in vitro. No clinical trial has tested cryptolepis for any bacterial infection (UTI, respiratory, enteric), so the traditional systemic-antibacterial use remains mechanistically supported but clinically unproven — and the most bactericidal fraction (chloroform) is not the traditional water decoction.

Cryptolepine is a topoisomerase II poison and DNA intercalator, and a large mechanistic literature maps this onto multiple cancer pathways — almost all of it in cell lines, with a few mouse xenografts. In colorectal cancer cells it suppresses proliferation, stemness and metastatic behaviour by inhibiting WNT/β-catenin signalling, outperforming a reference WNT inhibitor ^{15Reference 15Quarshie et al. · 2023In vitroCryptolepine suppresses colorectal cancer cell proliferation, stemness, and metastatic processes by inhibiting WNT/β-catenin signaling — in vitroView study →}; in hepatocellular carcinoma cells it downregulates IL-6/STAT3 signalling ^{16Reference 16Domfeh et al. · 2021In vitroCryptolepine inhibits hepatocellular carcinoma growth through inhibiting interleukin-6/STAT3 signalling — in vitroView study →}; in breast cancer models it blocks HIF-1-mediated glycolysis and slowed tumour growth in a 4T1 xenograft ^{17Reference 17Zheng et al. · 2022In vitroCryptolepine suppresses breast adenocarcinoma via inhibition of HIF-1 mediated glycolysis — in vitro and mouse xenograftView study →}; and in triple-negative breast cancer cells it modulates mutant p53 to trigger cell-cycle arrest and apoptosis ^{19Reference 19Qayoom et al. · 2024In vitroMutant p53 modulation by cryptolepine through cell cycle arrest and apoptosis in triple negative breast cancer — in vitroView study →}. The most complete in vivo work is in melanoma, where cryptolepine inhibited human melanoma (but not normal melanocyte) growth in vitro and reduced A375 xenograft growth in nude mice via AMPKα-LKB1 activation and disrupted mitochondrial dynamics ^{18Reference 18Pal et al. · 2017In vitroCryptolepine inhibits melanoma cell growth through coordinated changes in mitochondrial biogenesis, dynamics and the metabolic tumor suppressor AMPKα1/2-LKB1 — in vitro and mouse xenograftView study →}. Reviews frame cryptolepine as a genuine anticancer lead ^{14Reference 14Ansah et al. · 2013ReviewA review of the anticancer potential of the antimalarial herbal Cryptolepis sanguinolenta and its major alkaloid cryptolepine — reviewView study →}.

Gap: entirely preclinical and centred on isolated cryptolepine, not the herb; the same DNA-intercalating cytotoxicity that kills tumour cells is nonspecific (see Safety), and no data establish a therapeutic window in humans.

Cryptolepine has reproducible anti-inflammatory activity in rodent models. Given intraperitoneally (10–40 mg/kg), it produced dose-dependent inhibition of carrageenan-induced paw oedema and pleurisy in rats — comparable to indomethacin — plus reduced LPS-induced microvascular permeability and analgesia in the writhing test, without causing gastric lesions on four days of oral dosing ^{20Reference 20Olajide et al. · 2009AnimalAnti-inflammatory properties of cryptolepine — animal modelView study →}. Mechanistically it suppresses NF-κB DNA binding and, in LPS-activated microglia and IL-1β-stimulated neuroblastoma cells, lowers TNF-α, IL-6, IL-1β, nitric oxide and PGE2 while downregulating iNOS and COX-2 via NF-κB and p38 MAPK inhibition ^{21,22Reference 21Olajide et al. · 2013In vitroInhibition of neuroinflammation in LPS-activated microglia by cryptolepine — in vitroView study →Reference 22Olajide et al. · 2013In vitroAnti-neuroinflammatory properties of synthetic cryptolepine in human neuroblastoma cells: possible involvement of NF-κB and p38 MAPK inhibition — in vitroView study →}.

Gap: the in vivo data use injected isolated cryptolepine at doses far above anything achievable from the root tea; there is no human anti-inflammatory data and no oral dose-response for the whole herb.

This is the signal driving much of cryptolepis’s current Western popularity. In a controlled screen of botanical medicines against Borrelia burgdorferi, cryptolepis was one of the two most active herbs, showing strong activity against both growing (MIC 0.03–0.06%) and non-growing stationary-phase spirochetes; critically, a 1% cryptolepis extract achieved complete eradication in subculture, whereas the standard antibiotics doxycycline and cefuroxime did not ^{5Reference 5Feng et al. · 2020In vitroEvaluation of natural and botanical medicines for activity against growing and non-growing forms of B. burgdorferi — in vitroView study →}.

Gap: in vitro only, from a single research group, using an ethanol extract; there are no animal or human studies, and in vitro eradication of cultured spirochetes does not establish clinical efficacy against Lyme disease or its persistent symptoms.

In the companion Johns Hopkins screen, cryptolepis was among the botanicals with good in vitro activity against Babesia duncani in a hamster-erythrocyte model, and its alkaloid cryptolepine had an IC50 of ~3.4 μM — comparable to or lower than the clinical drugs quinine (~10 μM) and clindamycin (~37 μM). Cryptolepine at ≥1× IC50 and the 90% ethanol extract at 2–8× IC50 prevented parasite regrowth in subculture ^{6Reference 6Zhang et al. · 2021In vitroBotanical medicines Cryptolepis sanguinolenta, Artemisia annua, Scutellaria baicalensis, Polygonum cuspidatum, and Alchornea cordifolia demonstrate inhibitory activity against Babesia duncani — in vitroView study →}.

Gap: a single in vitro study; no animal or human data exist for babesiosis, and the favourable IC50 is for isolated cryptolepine, not the drunk preparation.

Cryptolepine was identified through ethnobotanically-directed fractionation as the antihyperglycemic principle of the root: it stimulates glucose uptake in 3T3-L1 adipocytes and lowers blood glucose in rodent models of type II diabetes ^{23Reference 23Bierer et al. · 1998In vitroEthnobotanical-directed discovery of the antihyperglycemic properties of cryptolepine: its isolation from Cryptolepis sanguinolenta, synthesis, and in vitro and in vivo activities — in vitro and animal in vivoView study →}. A later study attributed part of the effect to inhibition of intestinal glucose absorption and transport by the ethanol stem extract ^{24Reference 24Ajayi et al. · 2012In vitroEffect of ethanolic extract of Cryptolepis sanguinolenta stem on in vivo and in vitro glucose absorption and transport — animal and in vitroView study →}; a dedicated review collates the mechanism and rodent efficacy ^{25Reference 25Osafo et al. · 2017ReviewPhytochemical and pharmacological review of Cryptolepis sanguinolenta — reviewView study →}.

Gap: all data are rodent or in vitro and centre on isolated cryptolepine; there is no human trial, and the hypoglycaemic activity is more a pharmacological curiosity (and interaction hazard — see Safety) than an established use.

Cryptolepis has consistent in vitro activity against mycobacteria. Cryptolepine hydrochloride is a potent antimycobacterial alkaloid active against several Mycobacterium species ^{12Reference 12Gibbons et al. · 2003In vitroCryptolepine hydrochloride: a potent antimycobacterial alkaloid derived from Cryptolepis sanguinolenta — in vitroView study →}, the root aqueous extract had the highest antimycobacterial activity among seven Ghanaian plants tested against M. ulcerans (Buruli ulcer), MIC 64 μg/mL ^{13Reference 13Amponsah et al. · 2021In vitroIn vitro anti-Mycobacterium ulcerans and cytotoxic activities of some selected medicinal plants and an indoloquinoline alkaloid — in vitroView study →}, and methanolic root extracts are active against M. smegmatis and both pan-sensitive and rifampicin-resistant M. tuberculosis strains, positioning the herb as a source of anti-TB drug leads ^{32Reference 32Tuyiringire et al. · 2022In vitroIn vitro antimycobacterial activity of medicinal plants Lantana camara, Cryptolepis sanguinolenta, and Zanthoxylum leprieurii — in vitroView study →}.

Gap: in vitro only, and the cytotoxicity of cryptolepine complicates its use as a systemic anti-TB agent; no in vivo or clinical antimycobacterial data.

Several of the alkaloids active against bacteria also inhibit fungi in vitro. Cryptolepine, neocryptolepine, biscryptolepine and cryptoquindoline show activity against Candida albicans, dermatophytes (Trichophyton, Microsporum, Epidermophyton), Aspergillus niger and Saccharomyces cerevisiae ^{11Reference 11Cimanga et al. · 1998In vitroAntibacterial and antifungal activities of neocryptolepine, biscryptolepine and cryptoquindoline, alkaloids isolated from Cryptolepis sanguinolenta — in vitroView study →}.

Gap: antifungal potency is generally weaker than the antibacterial activity, the data are in vitro and alkaloid-based, and no clinical antifungal use is documented.

Cryptolepine and its derivatives have antiprotozoal activity beyond malaria. Cryptolepine induces apoptosis-like death in Leishmania donovani promastigotes, and the synthetic analogue 2,7-dibromocryptolepine is more active than the parent alkaloid ^{26Reference 26Hazra et al. · 2012In vitroAntileishmanial activity of cryptolepine analogues and apoptotic effects of 2,7-dibromocryptolepine against Leishmania donovani promastigotes — in vitroView study →}; various cryptolepine and neocryptolepine derivatives show antitrypanosomal activity against Trypanosoma brucei and T. cruzi targets in vitro.

Gap: the useful activity is largely in semisynthetic analogues rather than the natural alkaloid or the herb; all data are in vitro, with no in vivo or clinical support.

Cryptolepis has a reassuring acute-toxicity profile as traditionally used — a rodent LD50 above 5000 mg/kg and an open-label malaria trial reporting no clinical or laboratory toxicity over five days of root tea ^{1Reference 1Bugyei et al. · 2010Clinical trialClinical efficacy of a tea-bag formulation of Cryptolepis sanguinolenta root in the treatment of acute uncomplicated falciparum malaria — clinical trialView study →} — but this should not be read as “harmless.” The herb’s principal alkaloid, cryptolepine, is a DNA-intercalating topoisomerase inhibitor that is potently and non-selectively cytotoxic to mammalian cells in vitro ^{27Reference 27Ansah et al. · 2002In vitroThe popular herbal antimalarial, extract of Cryptolepis sanguinolenta, is potently cytotoxic — in vitroView study →}, and both the aqueous root extract and cryptolepine induce micronuclei (a marker of chromosomal damage) in mammalian cells, indicating genotoxic potential at higher exposures ^{28Reference 28Ansah et al. · 2005In vitroIn vitro genotoxicity of the West African antimalarial herbal Cryptolepis sanguinolenta and its major alkaloid cryptolepine — in vitroView study →}. Because the active constituent lowers blood glucose in animal models ^{23Reference 23Bierer et al. · 1998In vitroEthnobotanical-directed discovery of the antihyperglycemic properties of cryptolepine: its isolation from Cryptolepis sanguinolenta, synthesis, and in vitro and in vivo activities — in vitro and animal in vivoView study →}, cryptolepis may add to the effect of antidiabetic drugs, and it should be treated with caution alongside CNS depressants; concentrated, isolated-alkaloid, or long-term high-dose use carries more risk than short-term traditional decoctions.

The herb’s growing popularity in long-term, high-dose Lyme and Babesia protocols deserves an explicit caution: the anti-Borrelia and anti-Babesia data are in-vitro only ^{5,6Reference 5Feng et al. · 2020In vitroEvaluation of natural and botanical medicines for activity against growing and non-growing forms of B. burgdorferi — in vitroView study →Reference 6Zhang et al. · 2021In vitroBotanical medicines Cryptolepis sanguinolenta, Artemisia annua, Scutellaria baicalensis, Polygonum cuspidatum, and Alchornea cordifolia demonstrate inhibitory activity against Babesia duncani — in vitroView study →} and do not validate the prolonged high-dose regimens now common — a concern sharpened by the genotoxicity findings above.

No dedicated human drug-interaction or CYP450 study has been performed, so interactions with cryptolepis are not formally established; the antidiabetic and CNS-depressant cautions above are pharmacodynamic and traditional, not trial-derived. The absence of reported interaction problems is not evidence of safety.