Family • Apocynaceae - Voacanga globosa (Blanco) Merr.

Scientific names

Voacanga globosa (Blanco) Merr.
Voacanga cumingiana Rolfe
Voacanga dolichocalyx Quisumb. & Merr.
Voacanga latifolia Quisumb. & Merr.
Tabernaemontana globosa Blanco

Common names

Bayag usa (Tag.)
Lapit-usa (Bulusan, Sorsogon)
Tambagisa (Lanao del Norte)
Testicle tree (Engl.)


Bayag-usa is a tree reaching a height of up to 3 meters. Leaves are simple, opposite, oblong-elliptic; dark green in the upper surface and pale beneath. Flowers are creamy white and showy. Fruit comes in pairs, brownish, 3 to 5 centimeters in diameter. Seeds are embedded in the pulp.

– Endemic to the Philippines.
– In secondary forests and thickets at lower elevations.
– Sometimes ornamentally cultivated for its flowers.

Additional Sources and Suggested Readings

(1) Lapit-usa: Testicle Tree / Bulusan, Flora and fauna, Nature / Bulusan Rural Vagabond

(2) Tambagisa / Voacanga globosa (Blanco) Merr. / Philippine Traditional Knowledge Digital Library on Health

(3) Apoptosis-inducing activity of HPLC fraction from Voacanga globosa (Blanco) Merr. on the human colon carcinoma cell. / Acebedo AR, Amor EC, Jacinto SD. / Asian Pac J Cancer Prev. 2014;15(2):617-22

(4) Antimicrobial activity, cytotoxicity, and phytochemical screening of Voacanga globosa (Blanco) Merr. leaf extract (Apocynaceae). / Vital PG, Rivera WL. / Asian Pac J Trop Med. 2011 Oct;4(10):824-8. doi: 10.1016/S1995-7645(11)60202-2.

(5) Mycobacterium tuberculosis and cholinesterase inhibitors from Voacanga globosa. / Macabeo AP, Vidar WS, Chen X, Decker M, Heilmann J, Wan B, Franzblau SG, Galvez EV, Aguinaldo MA, Cordell GA. / Eur J Med Chem. 2011 Jul;46(7):3118-23. doi: 10.1016/j.ejmech.2011.04.025. Epub 2011 Apr 19.


– Preliminary phytochemical screening of leaves yielded alkaloids, saponins, 2-deoxysugars, and hydrolyzable tannins.
– A bioassay-guided purification yielded Globospiramine, a new spirobisindole alkaloid possessing an Aspidosperma-Aspidosperma skeleton, together with deoxyvobtusine, deoxyvobtusine lactone, vobtusine lactone and lupeol.


– Studies have suggested anti-tumor, antimycobacterial, and anticholinesterase properties.


– In Bataan, used in the treatment of ulcers, wounds, and tumors.
– Fruit used as antidote for food poisoning.

– Pounded fruits used to stupefy eels.

bayag-usa4Study Findings
• Anti-cancer: A study reports nine of 35 tree species tested had positive anticancer activity. Voacanga globosa was added to the list of trees with anticancer substances based on a report on actual remission and inhibition of induced cell division.
• Alkaloids / Tabernaemontanine: Further studies on the alkaloids of Voacanga globosa (Blanco) Merrill Isolation and characterization of tabernaemontanin.
• Anticancer: Study of medicinal plants in the Philippines lists nine of 35 tree species to possess anticancer activity, including Voacanga globosa, with anticancer substances based on remission and inhibition of induced cell division.
• Anti-Colon Cancer / Apoptosis: Study evaluated the cytotoxic and pro-apoptotic activity of fractions of leaves on HCT116 human colon carcinoma and A549 human lung carcinoma cell lines. Results showed the MP3 fraction exerted cytotoxic activity on HCT116 cells via induction of apoptosis triggered by loss of mitochondrial membrane potential crucial for cell survival.
• Antibacterial / Antifungal / Antiprotozoal / Leaves: Study evaluated ethanol extracts of leaves of Voacanga globosa for cytotoxicity and for activity against bacteria, fungus, and protozoa. Results showed antibacterial activity against Staph aureus, Bacillus cereus, P. aeruginosa, Micrococcus luteus, and Salmonella typhimurium; antifungal assay showed inhibition of Candida albicans; antiprotozoalassay showed activity against Trichomonas vaginalis and Entamoeba histolytica.
• Antimycobacterial / Anticholinesterase: Bioassay-guided purification yielded globospiramine, a new spirobisindole alkaloid, together with deoxyvobtusine, deoxyvobtusine lactone, vobtusine lactone, and lupeol. Globospiramine exhibited potent antituberculosis activity against Mycobacterium tuberculosis H Rv. The bisondole alkaloids also showed promising anticholinesterase activity.