Supplements & Herbs

St. John's wort (Hypericum perforatum) & cancer

Scientific research studies

by copyright © 2016 Healing Cancer Naturally

The medicinal plant St. John's wort and its principal active compounds such as hypericin, hyperforin and other constituents have been very widely researched. The following list focuses on studies relating to its potential effect on malignant disease, both in treating and preventing cancer.

Most of the studies listed are gleaned from the biomedical database PubMed which only features scientifically validated research.

St. John's wort and cancer

  • Eminent cancer researcher Prof. Dr. Dr. Paul Gerhardt Seeger
    one of whose books gives a ringing endorsement of herbalist Maria Treben's "miracle cures" devotes much space to the "miracle plant" (his words) Hypericum perforatum. Dr Seeger mentions research involving St. John's wort by

    * J. DITTMANN (1964) who found that Hypericum perforatum extract increases oxygen uptake by blood plasma.[1]

    * Karl DANIEL who found that strongly diluted hypericin solutions increased the cellular respiration of yeast cells. Rabbits, lambs and piglets given strongly diluted hypericin solutions showed increased appetite, faster growth and weight gain, as well as shinier furs and greater vitality, with the same results confirmed by a number of other researchers.

    In humans, besides the well-known effects on depression, fear etc., the administration of strongly diluted hypericin solutions improved or healed anemia as well as diabetes linked to malfunction of the pituitary gland. It also had a vitalising, appetite-increasing and metabolism-enhancing effect.[2]

    * SEEGER and SCHACHT who in 1960/62 were able to normalise the damaged cellular respiration in murine (mouse) cancer cells.[3]

    The natural colourings found in Hypericum contain hydrogen acceptors, its high choline content stabilises the disintegrated cellular phospholipids. Choline thus has a regenerating effect on cell membrane permeability. Its high manganese content of 12 % exerts a considerable influence upon the oxydation systems of the citric acid cycle.
    Dr. Seeger summarises the value of St. John's wort by writing that "Hypericum extract provides us with a reliable remedy, effective both prophylactically and therapeutically, against cellular respiration disturbances which cause a multitude of diseases".
  • Cytotoxic activity of Hypericum perforatum L. on K562 erythroleukemic cells: differential effects between methanolic extract and hypericin.

    This interesting study (published in Phytotherapy Research in 2004) highlighted the impact an extract of the whole St. John's wort flower had on the growth of human leukemia cells vs that of purified (isolated) hypericin.

    While the isolate (hypericin) only showed a weak inhibitory effect on cell growth and did not induce apoptosis (cell death), the extract of the whole St. John's wort flower did impair tumor cell growth in a significant and long-lasting manner and induced apoptosis.

    This study also "confirms the interesting role of Hypericum perforatum L. in cancer therapy".
  • Mechanistic insights into the antileukemic activity of hyperforin.

    Hyperforin inter alia is known for its antitumor, anti-inflammatory, and antibiotic/antibacterial properties. This in-vitro study (Current Cancer Drug Targets, 2013) looked into the effects of hyperforin and its derivatives in chronic lymphoid leukemia and acute myeloid leukemia (both of which don't respond well to chemotherapy) and found the compounds to be promising antileukemic agents.
  • Growth inhibition of malignant glioblastoma by DING protein.

    This study (Journal of neuro-oncology, 2012) found that a novel protein compound derived from St. John's wort calluses inhibits the growth of glioma cells, making it a potential therapeutic agent in the treatment of malignant gliomas.
  • Induction of apoptosis in K562 cells by dicyclohexylammonium salt of hyperforin through a mitochondrial-related pathway.

    This study (printed in Chemo-Biological Interactions in 2011) showed that the dicyclohexylammonium salt of hyperforin whose antitumor and antiangiogenic properties had previously been demonstrated in various other cancer cell lines, also works against chronic myeloid leukemia cells.
  • Mechanisms of Hyperforin as an anti-angiogenic angioprevention agent.

    Hyperforin's biological properties include inhibition of tumour invasion and angiogenesis. Among many other results, this study (which appeared in the European Journal of Cancer in 2009) demonstrated that Hyperforin strongly inhibited inflammation- or tumour-triggered angiogenesis and the growth and vascularisation of Kaposi's sarcoma tumours.
  • St. John's Wort Attenuates Colorectal Carcinogenesis in Mice through Suppression of Inflammatory Signaling.

    For this study (Cancer Prevention Research, 2015), a number of hapless mice were split into two groups, one was fed a control diet, the other a diet supplemented with St. John's wort extract. Both were then treated with a chemical compound used to induce colon cancer.

    The mice pretreated with St. John's wort extract had significantly improved overall survival, less tumors and body weight loss as well as improvement in other parameters associated with the artificially induced colorectal tumors. This study could point at the potential of St. John's wort extract against colorectal cancer.
  • Evaluation of antitumor activity of peptide extracts from medicinal plants on the model of transplanted breast cancer in CBRB-Rb(8.17)1Iem mice.

    This study (Bulletin of Experimental Biology and Medicine, 2008) found that extracts of St. John's wort as well as a mixture of other plants showed maximum antitumor effects in a mouse model of slowly growing mammary adenocarcinoma.
  • Pro-apoptotic properties of hyperforin in leukemic cells from patients with B-cell chronic lymphocytic leukemia.

    This study (published in Leukemia in 2006) looked into hyperforin's effects on malignant B-cell chronic lymphocytic leukemia cells. Hyperforin promoted the apoptosis of these cells, inducing inter alia the downregulation of antiapoptotic proteins.
  • The lipophilic extract of Hypericum perforatum exerts significant cytotoxic activity against T24 and NBT-II urinary bladder tumor cells.

    This study (Planta Medica, 2005) showed the lipophilic extract of St. John's wort as a promising antiproliferative agent with low toxicity against bladder cancer.
  • Hypericum perforatum methanolic extract inhibits growth of human prostatic carcinoma cell line orthotopically implanted in nude mice.

    Serotonin-reuptake inhibitors and serotonin antagonists have been shown to exert antiproliferative effects in prostate tumors. Components of St. John's wort act as serotonin-reuptake inhibitors and have demonstrated cytotoxic effects on a number of human cancer cell lines.

    This study (Cancer Letters, 2004) was able to show that St. John's wort extract significantly reduced the growth of human prostate cancer cells and number of metastases, indicating St. John's wort's potential usefulness against prostate cancer.
  • Hyperforin a constituent of St John's wort (Hypericum perforatum L.) extract induces apoptosis by triggering activation of caspases and with hypericin synergistically exerts cytotoxicity towards human malignant cell lines.

    This study (European Journal of Pharmaceutics and Biopharmaceutics, 2003) inter alia investigated the ability of Hyperforin to inhibit the growth of leukemia and glioblastoma cells and to induce cell death by apoptosis. Results showed St John's wort to be "an interesting option in cancer".
  • Effect of hypericin on the ADAMTS-9 and ADAMTS-8 gene expression in MCF7 breast cancer cells.

    This study (European Review for Medical and Pharmacological Sciences, 2013) showed Hypericin to possess antitumor and apoptopic effects in breast cancer cells. It can be read in its entirety at
  • Hyperforin induces apoptosis of chronic lymphocytic leukemia cells through upregulation of the BH3-only protein Noxa.

    (International Journal of Oncology, 2012)
  • Cytotoxic and apoptogenic effect of hypericin, the bioactive component of Hypericum perforatum on the MCF-7 human breast cancer cell line.

    (Cancer Cell International, 2016)

St John's Wort in cancer prevention

  • Water extracts of tree Hypericum sps. protect DNA from oxidative and alkylating damage and enhance DNA repair in colon cells.

    This study (published in Food and Chemical Toxicology in 2013) looked into the potential of aqueous extracts of three Hypericum species to act as anticarcinogenic compounds in the colon, protecting against DNA damage and thus helping to prevent colon cancer.
  • St. John's wort extracts and some of their constituents potently inhibit ultimate carcinogen formation from benzo[a]pyrene-7,8-dihydrodiol by human CYP1A1.

    Hypericin, hyperforin, pseudohypericin, quercetin and rutin are among the principal compounds found in St. John's wort extracts. This in-vitro study (Cancer Research, 2003) found these compounds to powerfully inhibit the major human procarcinogen-activating enzyme cytochrome P450 1A1.

    This study can be read in its entirety at .

St John's Wort in photodynamic cancer therapy

Photodynamic Therapy (PDT) is a minimally toxic treatment that allows the selective killing of microbes as well as cancer cells. PDT has been used to treat a variety of solid neoplasms in a minimally invasive manner, including nasopharyngeal carcinoma, bladder cancer, mesothelioma, skin cancer (incl. actinic keratosis, basal cell carcinoma, metastatic melanoma and morbus Bowen), ovarian cancer, head and neck cancer, lung cancer, and prostate cancer.

Photodynamic therapy is based on the local or systemic administration of a photosensitizing chemical which is selectively taken up in tumor cells or tissue. The tumor is then irradiated with visible light.

In the presence of oxygen, a cascade of oxidative events is triggered resulting in irreversible cell and tissue damage including tumor cell death and tumor destruction. In other words, photodynamic therapy takes advantage of the light-induced destruction of the target cells due to cytotoxic products being formed when a photosensitizing agent and oxygen come together.[4]

Hypericin found in St. John's wort is possibly the most powerful naturally occurring photosensitizer and increasingly used in photodynamic cancer therapy as well as for diagnostic purposes.

Studies: St John's Wort in photodynamic cancer therapy

  • Hypericin in cancer treatment: more light on the way.
  • Nitric oxide mediated photo-induced cell death in human malignant cells.
  • Hypericin as a potential phototherapeutic agent in superficial transitional cell carcinoma of the bladder. .
  • Hypericin lights up the way for the potential treatment of nasopharyngeal cancer by photodynamic therapy.
  • Photodynamic therapy of nonmelanoma skin cancer with topical hypericum perforatum extract—a pilot study.
  • Hypericin-loaded nanoparticles for the photodynamic treatment of ovarian cancer.
  • Cellular mechanisms and prospective applications of hypericin in photodynamic therapy.
  • Hypericum perforatum L. extract — novel photosensitizer against human bladder cancer cells.
  • St John's Wort (Hypericum perforatum L.) photomedicine: hypericin-photodynamic therapy induces metastatic melanoma cell death.
  • Hypericin-loaded lipid nanocapsules for photodynamic cancer therapy in vitro.
  • Hypericum perforatum L. subsp. perforatum induces inhibition of free radicals and enhanced phototoxicity in human melanoma cells under ultraviolet light.

Unfortunately (but as usual), the bulk of the above research is based upon animal experimentation or in-vitro studies.[5] Even if just half of these results were to be confirmed to equally apply to humans, St. John's wort would have clearly been shown to have healing and preventative potential for cancer.

A note of caution

St. John's wort is a powerful medicinal plant provided by nature. Interactions with manmade pharmaceutical drugs have been reported. Before deciding to use St. John's wort in tandem with any conventional drug treatment including chemotherapy, make sure to thoroughly research possible drug interactions.

Also see

St. John's wort (Hypericum perforatum): Cancer anecdotes.


1 (German-language). Cellular respiration or the lack thereof plays a key role in cancer, see The Prime Cause and Prevention of Cancer.

2 Kurze Mitteilung über 12jährige therapeutische Erfahrungen mit Hypericin, Klinische Wochenschrift, 1951, 29:260-262. and [Therapeutic use of hypericine].

3 Related research listed at and .

4 Also see the concise background information provided at On Photodynamic Therapy (PDT).

5 Both for ethical and scientific reasons, Healing Cancer Naturally does not support animal experimentation. For details see Cancer Research, Toxicity Testing & Animal Experimentation: an Unholy Union?.

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