Ocimum basilicum (Jansen, 1981)
Ocimum basilicum (Jansen, 1981)
2.8 Ocimum basilicum L.
’Ocimum’: derived from the Greek 'okimon', an old plant name for an Ocimum species; it may also be related to the Greek 'akinos' which cornes from 'ozein' = to smell, or from 'oxys' = sharp, because of the usually strong odour of the Ocimum species.
’basilicum’: derived from the Greek 'basilikos', 'basileus'= king; so, royal Ocimum, probably for its superb smell.
Linnaeus, Sp. Pl. ed. 1: p. 597 (1753).
Type: 'Habitat in India, Persia; Ocimum foliis ovatis glabris, calycibus ciliatis' (LINN 749.5, lecto.!).
- Ocimum americanum L., Centuria I. Plantarum A. D. Juslenius, no 41 (1755).
- Ocimum graveolens A. Braun, Flora 24(17): p. 265 (1841).
- Ocimum petitianum Richard, Tent. fl. Abyss. 2: p. 176 (1851).
A lot of other synonyms are known from literature, but only a thorough revision of the genus Ocimum L. might evaluate their correct status.
- 1775: Forskal, Fl. Aeg.-Arabica: p. 108-111. (tax.)
- 1832: Bentham, Labiatarum genera et species: p. 1-19. (tax.)
- 1848: Bentham, in: DC, Prodr. 12: p. 31-44. (tax.)
- 1859: Lenz, Botanik der alten Griechen und Romer: p. 87, 100, 513-514. (use)
- 1879: Boissier, Flora Orientalis 4: p. 539. (tax.)
- 1897: Briquet, in: Engler & Prantl, Die nat. Pflanzenfam., ed. 1, 4, 3a: p. 369-372. (tax.)
- 1900: Baker, in: Flora trop. Afr. 5: p. 334-348. (tax.)
- 1912: Chiovenda, Osservazioni botaniche, agrarie ed industriali, Monog. rapp. col. 24: p. 34, 57. (use)
- 1918: Rolet, Plantes à parfums et plantes aromatiques: p. 284-287. (agric.)
- 1927: Gams, in: Hegi, Illustr. Fl. Mittel-Eur. B. 5, T. 4, ed. 1: p. 2267-2270. (tax. + use)
- 1927: Heyne, De nuttige planten van Nederlandsch Indië, ed. 2: p. 1336-1337. (use)
- 1927: Ochse, Indische vruchten: p. 101-102. (use)
- 1930: Guillaumin, Les Ocimum à essence, Bull. Sc. Pharm. 37,2: p. 431-449. (tax. + use)
- 1934: Bois, Les plantes alimentaires chez tous les peuples et à travers les âges, 3, Plantes à épices, à aromates, à condiments: p. 178-182. (agric. + use)
- 1946: Baldrati, Piante officinali dell'Africa orientale, Centro Studi Colon. 32: p. 99-101. (use)
- 1950: Baldrati, Trattato delle coltivazioni tropicali e subtropicali: p. 206. (agric.)
- 1955: Dalziel, Useful pl. W. Trop. Afr., repr. 2: p. 462. (use)
- 1962: Morton, Cytotaxonomic studies on the West African Labiatae, Journ. Linn. Soc. (Bot.) 58, 372: p. 231-282. (tax.)
- 1963: Cufodontis, Enumeratio, Bull. Jard. Bot. État Brux. 33(3), suppl.: p. 845-849. (tax.)
- 1963: Morton, in: Flora West Trop. Afr., ed. 2, 2: p. 451-452. (tax.)
- 1963: Siegenthaler, Useful plants of Ethiopia, Exp. St. Bull. 14: p. 7. (use)
- 1966: Hegnauer, Chemotax. der Pfl., B. 4: p. 313-314. (chem.)
- 1969: Parry, Spices, 1: p. 217-218; 2: p. 149-152. (use)
- 1969: Rosengarten, The book of spices: p. 108-113. (use)
- 1973: Jain & Jain, Investigations on the essential oil of Ocimum basilicum, Planta Medica 24: p. 286-289. (chem.)
- 1974: Darrah, Investigation of the cultivars of the basils, Econ. Bot. 28: p. 63-67. (tax. + agric.)
- basobila, adjuban, hulkot, zakakewe (Amarinia)
- kassé, kefo, kendama, urgo, zahahene (Gallinia)
- sessak, sesseg (Tigrinia)
- rehan (Somalia)
- basil, common basil, sweet basil (English)
- basilic, basilic commun (French)
- Basilie, Basilienkraut, Basilikum, Konigskraut (German).
It is generally believed that Ocimum basilicum L. originates from Central tropical Asia, perhaps from India (Bentham, 1832), or from Iran or Afghanistan (Guillaumin, 1930). The distribution of basil, however, is now almost worldwide. It has been cultivated in many countries since ancient times and sometimes the plant has acquired a place in the wild flora. Obviously this happened also in Ethiopia, where the plant is found in cultivation as well as in the wild in most provinces. Fresh or dried plant parts are for sale on almost every Ethiopian market and small-scale cultivation near bouses is widespread. According to Baldrati (1950), several thousands of hectares of basil are cultivated in Ethiopia.
An erect, much branched annual, up to 75 cm high, with a brown, up to 6 mm thick taproot with many side-roots; aerial parts strong-smelling, especially when crushed.
- Stem quadrangular, up to 6 x 6 mm, usually rather densely white-pilose in young parts, less so when older, much branched at all heights, light-green to dark-purple.
- Leaves simple, decussate, petiolate; petiole up to 4.5 cm lon~pilose, light-green to purplish-green; blade ovate to narrowly so, usually ca twice as long as wide, up to 8 x 4 cm, acuminate, attenuate at base, sometimes somewhat obliquely so, margin crenate-serrate, usually shortly ciliate, pale-green and glabrous to scarcely pilose on veins above, often lighter green with purplish midrib and pilose on the slightly prominent veins below; leaves densely glandular punctate, in dried specimens often with brown or red-brown droplets of exudation.
- Inflorescence up to 30 cm long, composed of decussate, 3-flowered cymes, appearing as verticils, up to 3 cm apart; peduncle quadrangular, white-pilose, light-green to dark-purple; bracts oblanceolate to rhombate, up to 11 x 3 mm, acuminate, subcrenate-serrate, ciliate, pilose, light-green or purplish, usually persistent; pedicel
Fig. 9. Ocimum basilicum L. - 1. habit inflorescence (⅔x); 2. flower (6⅔x); 3. opened corolla with stamens (6⅔x); 4. pistil (6⅔x ); 5. calyx (6⅔x ); 6. nutlet (12x); 7. seedling (⅔x). -1-4. PJ 181 (spirit mat. too); 5-6. PJ 544; 7. PJ 86 (spirit mat.).
up to 4 mm long, densely white-pilose, at top strongly recurved, light-green to dark-purple.
- Calyx bilobed, tubular, with a sub-orbicular flat adaxial lobe and a canaliculate abaxial lobe, green to brown-purple, densely glandular punctate; tube conical at base, ca 1-1.5 mm long (in fruit ca 2 mm long), pilose at base outside, densely long hairy inside above the ovary; adaxial lobe in outline up to 3.5 x 3.5 mm (accrescent in fruit to 4.5 x 4.5 mm), slightly apiculate, 2-eared, ciliate, usually glabrous outside and glabrous to scarcely pilose inside, with prominent venation, especially so in fruit, with 3 sub-parallel ribs centrally; abaxial lobe up to 2.5 mm in diam. (in fruit to 3 mm), up to 3.5 mm long (in fruit to 4 mm), sharply 4-toothed at top, the two outer ones shorter than the central ones, slightly pilose, ciliate.
- Corolla tubular, two-lipped, whitish-purplish, usually darkest at the top of the lips; tube up to 4 mm long, the adaxial lip larger than the abaxial one, up to 2 x 6 mm, at top strongly recurved and crenately incised, forming four lobes which are pilose outside; centrally, near the base, a shallow pocket is present which is pilose on its convex outside; abaxial lip ovate, entire, flat or slightly concave, up to 3.5 x 2 mm, pilose near the top outside.
- Androecium: stamens 4, epipetalous, didynamous, more or less pressed against the abaxial lip, light-purplish, white and slightly pilose at base; the outer ones up to 7 mm long, inserted at ca 1 mm from the base of the corolla tube, provided with a white, pilose, downward directed, ca 0.5-1 mm long tooth at ca 1 mm above their base; the inner stamens up to 5 mm long, inserted near the throat of the corolla, one at each side of the abaxial lobe; anthers one-celled, basifixed, heartshaped, ca 0.6 x 0.75 mm, orange or white, initially dehiscing introrsely by an inversed v-shaped transverse slit.
- Gynoecium: ovary ca 1 x 1 mm in outline, light-green, with 4 ellipsoid, one-ovuled lobes, surrounded by a 4-lobed, white disc, the lobes alternating with and usually a bit shorter than the ovary lobes; style gynobasic, up to 9 mm long, white or light-purple, filiform; stigma white, 2-lobed, lobes 0.5-1 mm long, usually one lobe slightly longer than the other one.
- Fruit composed of four distinct nutlets, enclosed within the tube of the persistent calyx; nutlets ovoid, up to 1.25 mm long and 1 mm in diam., black or dark-brown, usually with a white scar at base, smoothly muricate; in water the nutlet-wall produces within some minutes a thick white cover of slimy threads.
- Seed free within the nutlet; testa white-brown; cotyledons greyish; endosperm scarce or absent.
- Seedling: germination epigeal; taproot with the many side-roots light-brown; hypocotyl up to 17 mm long, purplish, pilose; cotyledons opposite, with an up to 9 mm long, pilose petiole and a kidney shaped, up to 5 x 7 mm, entire, glabrous, light-green blade; epicotyl up to 4 cm long, densely pilose, light-green or purplish.
(1) In the protologue of Ocimum basilicum (Sp. Pl.: p. 597, 1753), Linnaeus referred to Hort. Cliff. 315, Hort. Ups. 168, Roy.lugdb. 322, Cam. epit. 308 and four times to Bauh. pin. 225-226. The phrase name ’Ocimum foliis ovatis glabris’,
originates from Hort. Cliff., is copied in Hort. Ups. and in Roy. lugdb., but extended with: 'calycibus ciliatis' in Sp. Pl. In the Hort. Cliff. herbarium (BM), under: '2. Ocimum foliis ovatis glabris', three specimens are present, representing three 'varieties' mentioned in Hort. Cliff., with phrase names originating from Boerhaave. For the three other 'varieties' mentioned in Hort. Cliff. by phrase names of Bauh. pin., no specimens are present. In Sp. Pl., Linnaeus copied only the varietal phrase names of Bauhin, not those of Boerhaave, which might indicate that Linnaeus was not sure about the identity of the latter ones. So it seems preferable not to look for the type specimen of O. basilicum in the Hort. Cliff. herbarium. The best choice as lectotype for this taxon is, in my opinion, specimen LINN 749.5, present in the Linnaean herbarium. Linnaeus extended the description with 'calycibus ciliatis' in 1753, and wrote ’basilicum 2’ on the sheet of this herbarium specimen, which number corresponds with the order of treatment in his Sp. Pl. The presence of the sign 'e' on the same sheet indicates that this specimen had most probably been collected by Gerber in the western edge of Asia (here cited as 'Persia' by Linnaeus). Linnaeus obtained this specimen before or around 1750 (see Stearn, Introd. Sp. Pl. p. 106, 1957). I designate as lectotype of Ocimum basilicum L. specimen LINN 749.5.
(2) The taxonomy of the genus Ocimum L. in the literature and in the herbaria is in extreme disorder. A thorough revision of the genus is badly needed. Bentham (1848) distinguished nine varieties of O. basilicum, but the description of these varieties is rather vague, making identification impossible. Gams (1926) distinguished only 3-4 varieties of Bentham's (with or without O. minimum L.), and classified Bentham's other varieties as subvarieties or formas. He also accommodated some taxa described by Alefeld (1866). Gams' descriptions however are as vague as those of Bentham and I cannot satisfactorily order the basils in Ethiopia by Bentham's or Gams' classification. To avoid adding new names to the already overloaded group of Ocimum names, I just distinguish groups here and provide them, for convenience only, with a group name, neither intending to publish new taxonomic names nor to give the groups a taxonomic status, as this ought to be postponed till the genus Ocimum is revised worldwide.
(3) The first group I indicate as ’basobila’ group, 'basobila' being the most common name for those plants in Ethiopia. To this group belongs the majority of the cultivated basils in Ethiopia and the chapter on O. basilicum in this book primarily deals with this group (description, figure, etc.). The 'basobila' group certainly belongs to the taxon O. basilicum L. The specimens may differ considerably if grown at different localities. Plants grown in Ethiopia were in general more robust than the more or less etiolated plants grown in a greenhouse at Wageningen. Differences after growing plants (originating from the same seed) at different localities and under different conditions (Wageningen, greenhouse; Alemaya, alt. ca 2000 m; Melkassa near Nazareth, alt. ca 1500 m), are given in Table 6 (differences in average largest sizes).
(4) I call the second group of basils cultivated in Ethiopia the ’alemu’ group (after Mr Alemu Temesgen, who cultivated this taxon at Jimma and Nazareth). The main differences from the 'basobila' group are:
- The plants have a woody base
- The plants have a strong fresh lemon odour
plants from Ethiopia cultivated at three localities.
|total plant height||35 cm||40 cm||60 cm|
|petiole length||31 mm||19 mm||36 mm|
|leaf-blade||5.6 x 2.8 cm||5.5 x 2.7 cm||7 x 3.5 cm|
|inflorescence length||20 cm||15 cm||28 cm|
|verticillasters distance||18 mm||15 cm||21 mm|
|bracts||5.5 x 1.5 mm||4.5 x 1.5 mm||9 x 2 mm|
|pedicel length||3.5 mm||2 mm||3.5 mm|
|corolla length||6 mm||5.5 mm||7 mm|
|stamens length||6 mm||4 mm||7 mm|
|pistil length||7.5 mm||6 mm||8.5 mm|
|ventral calyx lobe in fruit||4 x 4 mm||3.5 x 3.5 mm||4 x 4 mm|
- The leaf-blades are anguste-ovate, up to 8 x 3 cm
- The stamens are up to 9 mm long
- The style is up to 11.5 mm long
- The adaxial lobe of the calyx in fruit is up to 6 x 5 mm and the abaxial lobe up to 9 x 6mm
- The nutlets are up to 2 mm long and 1.5 mm in diam.
(5) I call the third group of cultivated basils in Ethiopia the ’thyrsiflorum’ group, as the plants are identical with Ocimum thyrsiflorum L. The main differences from the 'basobila' group are:
- The plants have a woody base and are up to 1 m high
- The plants have a fresh lemon smell
- The leaf-blades are elliptic to anguste-ovate, up to 7 x 2.5 cm
- The inflorescences are repeatedly decussately branched, ending in very short ultimate branchlets with 2-3 verticillasters of opposite 3-flowered cymes.
(6) The fourth group of basils in Ethiopia is formed by plants growing in the wild, but sometimes offered for sale on the markets. I call this group the 'wild' group. The plants are woody and perennial. They are close to O. basilicum, but are often identified as O. canum Sims or as O. menthaefolium Hochst. ex Benth. The differences between many of the described species of Ocimum related to O. basilicum, are very small, and if a perennial and woody character is accepted for O. basilicum, the differences might be better expressed at a varietal level. In fact I have observed in Alemaya, Ethiopia, that plants of the 'basobila' group recommenced growth and flowering the second year after sowing. Only a thorough revision may unravel the systematics of Ocimum.
(7) The description of the 'basobila' group is based on the following specimens:
Arussi Begemdir Hararge
Sire market: SL 144. Debarek market: WP 4969. Alemaya, cultivated at the College of Agriculture: Bos 8030, PJ 1815, PJ 2799-2800, PJ 2810, PJ 2945, PJ 4024-4025, PJ 4052, PJ 4330-4331, PJ 4343; Alemaya market: PJ 1173, PJ 5907; Asbe Tefari market: SL 4; Dire
Kefa Shoa Sidamo Wollega Grown at Dawa market: WP 133, Bos 8352, Bos 8383, PJ 1034; Harar market: WP 72, WP 370, Bos 8037-8038, PJ 1552-1553. Agaro market: SL 2668; Jimma market: Bos 8627; growing in the wild near Wush-Wush: PJ 5410. Ambo market: PJ 1219, PJ 1223; Bulbulla market: PJ 3910-3911; Melkassa, cultivated at Inst. of Agric. Res., Nazareth: PJ 2409, PJ 2435-2436, PJ 3576-3578, PJ 4699-4 701; 67 km from Shashemene on road to Kolito, in field: WP 2853. Dilla, 8 km on road to Wondo, in garden: WP 2827. Bako market: PJ 1212; Ghimbie market: PJ 1174, PJ 1182; Nekemt market: PJ 1193A, PJ 1197-1198. Wageningen PJ 85-86, PJ 142-143, PJ 181-182, PJ 392-393, PJ 544-545, PJ 761-762, WP 6089-6091, WP 7378-7379.
The following specimens, originating from Ethiopia, were seen: A. de Benedictis 423 (Fr), 442 (Fr); E. Chiovenda 89 (Fr), 2560 (Fr), s.n. 16-5-1939 (Fr); M. Mariottini 377 (Fr), 381 (FT); Petit s.n. (ex herb. de Franqueville), Abyssinie (P); R. Pichi-Sermolli 1414 (FT); Quartin Dillon & Petit s.n. Choho (P), Etchelikote (O. petitianum Rich.) (P); P. Rovesti 17 (Fr); W. Schimper s.n. (herb. Steudel) (P); G. Schweinfurth & D. Riva 96 (K).
(8) The observations on the 'alemu' group are based on the following specimens:
Hararge Shoa Kef a Alemaya, in garden, ait. 2000 rn: WP 784. Nazareth, spice garden of the Inst. of Agr. Res. at Melkassa, ait. 1500 rn: PJ 2437. Jimma, spice garden of the Inst. Agr. Res., alt. 1740 rn: PJ 5844. The following specimens, originating from Ethiopia, were seen: P. R. O. Bally 11023 (K); A. de Benedictis 161 (Fr); J. W. Colville 37 (K), 91 (K); Th. Kotschy, Sennaar 198 (herb. Steudel) (P); M. Mosk 284 (K); H.F. Mooney 8058 (K, Fr); Quartin Dillon & Petit s.n. (herb. de Franqueville (K); Ruspoli & Riva 371 ( 402) (1974) (Fr); Schimper 294 (K); W. G. Schimper s.n. 21 Okt. 1854 Dschedscha (P); H. Smeds 1276 (K); Willemse 16610/20 (K).
(9) The observations on the 'thyrsiflorum' group are based on the following specimens:
Hararge Shoa Tigre Wollo Asbe Tefari market: WP 1300; Harar market: Bos 8055. Bulbulla market: PJ 3905; Nazareth-Melkassa, spice garden Inst. of Agr. Res.: PJ 2442. Adishow market: SL 3058. Bati market: WP 4011A.
(10) From the 'wild' group the following specimens, originating from Ethiopia, were seen: P. R. O. Bally 6736 (K), 6799 (K), 6865 (K), 6931 (K); Bos 7845 (WAG), 7931 (WAG), 8171 (WAG), 8232 (WAG), 10059 (WAG); F. Brown 58 (K); W. Burger 798 (ACD, K); W. Burger & Amare Getahun 343 (ACD, K); Collenette 241 (K); R. Corradi 5451 (Fr); P. E. Ellis 213 (K); PJ 3026 (WAG), 3188 (WAG), 3759 (WAG), 4974 (WAG), 6923 (WAG); Kotschy 568 (K); J. K. Lord 8169 (K); C. Parker E.468 (K), E.553 (K); R. E. Perdue 6508 (K); J. Pfund 483 (K); R. Pichi-Sermolli 1413 (Fr), 1415 (Fr); Quartin Dillon & Petit s.n. (herb. de Franqueville) (K), Chiré (herb. Richard) (P); Ruspoli & Riva 1177 (1300) (799)
(1077) (FT); Schimper 425 (K); Siegenthaler 1536 (K); Speke & Grant s.n. (K); J. E. Strecker s.n. (K); Tadesse Ebba 519 (ACD, WAG); P. Townsend 62 (K); WP 1440-1441 (WAG), 4071 (WAG).
Basil should be cultivated in sunny wind-sheltered spots and even light frosts will kill the plants (Gams, 1926; Rosengarten, 1969). According to Ochse (1927) in Indonesia basil is cultivated at altitudes below 500 m, but Heyne (1927) states that basil is cultivated there up to ca 1100 m. In Ethiopia the cultivation of basil is possible up to at least 2000 m altitude, where the plants can stand some light frost (pers. obs. 1975-1977).
Photograph 15. Ocimum basilicum, detail of photograph 16.
Basil provides a good food for bees. Insect pollination is normal; the pollen sticks to the underside of the insect as it enters the flower by walking over the lower lip of the corolla on which the stamens and pistil are situated. The pistil is slightly longer than the stamens but this does not preclude self-pollination (Gams, 1926). According to Darrah (1974), self-pollination in basil can give viable seed, but less of it than by open pollination.
Basil is easily propagated by seed. According to Gams (1926) the seeds keep their viability for 4-5 years without special preservation. Sowing is done either directly in the field or first in a nursery. Seed is usually sown directly in the field in rows 50-75 cm apart and at ca 5 kg/ha (Rosengarten, 1969). Within the rows, the seedlings are thinned to ca 15-30 cm a part. If sown in a nursery, the plants are transplanted when they have 4-6 normal leaves (Guillaumin, 1930). The plants do not require a special soil but seem to prefer sunny wind-sheltered spots (Rosengarten, 1969). Germination normally takes 1-2 weeks. In Ethiopia however, basil seeds germinated only after 1.5 month, flowering started ca 1 month later and fruits could be harvested 4-4.5 months after sowing. At Wageningen in a greenhouse, germination took 3 weeks, flowering started 2 months after sowing and fruits could be collected 3 months after sowing (pers. obs. 1974-1977). In Pennsylvania (USA) various basil cultivars differed considerably in the time taken to reach flowering (Darrah, 1974).
Weed control is important, as weeds, included in the harvested crop, might impair or ruin its quality (Rosengarten, 1969). For production of essential oil, the young leafy stems are harvested just before the flowers appear. The plants are only partly cut back so that un der favourable circumstances addition al crops may be obtained. In California, the crop is eut 3--4 times per year and a total yield of fresh herb can be 25 000 kg/ha. Before the leaves are marketed, they are dried artificially under caver at a temperature of ca 40°C, to preserve the green colour (Rosengarten, 1969). Rolet (1918) claimed that maximum oil content was obtained if the plants were protected against too strong light but did not say why. The essential oil is produced by steam-distillation of the fresh herb and the yield can be up to 30 kg/ha (Rosengarten, 1969). Instead of foliage, the dry or fresh inflorescences (with or without some leaves and stem-parts) are usually harvested in Ethiopia and directly used in food.
From Italy, Cuscuta australis R. Br. var. breviflora (Vis.) Engelm. is reported to parasitize basil (Gams, 1926). In Shoa Province of Ethiopia, Stewart and Dagnatchew (1967) observed a downy mildew, Peronospora sp., on basil.
Being already a well known herb to the Ancient Greeks and Romans, basil has long been used as a culinary herb. The dried and fragmented leaves are used to flavour many kinds of foods like stews, sauces, salads, soups and meats. In the USA, it is
Photograph 16. Ocimum basilicum, flowering plant, PJ 392.
particularly used in tomato-based recipes (Rosengarten, 1968). In Indonesia, the leaves, either raw or cooked, are used mainly to flavour fish and meat dishes (Heyne, 1927). According to Ochse (1927), the seeds of basil, mixed in syrups, are used in Indonesia in the preparation of cold drinks. The essential oil of basil is used in many perfumes and it is a major ingredient of the liqueur chartreuse (Rosengarten, 1969). In Ethiopia both dried and fresh inflorescences and leaves of basil are used almost daily as a flavouring agent in the preparation of all kinds of 'wot'. Usually the leaves, flowers, fruits and tender stems of basil are dried, ground and added to sauces, together with other spices. Basil is highly appreciated as some Ethiopians consider spice mixtures lacking basil as worthless. Dried ground basil is also used to flavour
butter and is sometimes sprinkled in tea or coffee to add flavour (Telahun, 1962; Siegenthaler, 1963).
In antiquity and in the Middle Ages, basil was associated with superstitions. In Ancient Greece, sweet basil was the symbol of hatred. In Ancient Rome, it was believed that if basil was pounded and left beneath a stone, a scorpion would breed in its midst, and if chewed and left in the sun, worms would breed in it (Lenz, 1859; Gams, 1926).
In general, basil has been used or is used for external application against snake and scorpion bites, eye diseases and rheumatic pains; for internal use as an aphrodisiac, as a diuretic and as a purgative (Gams, 1926). The odour of basil is reputed to relieve headaches, fevers (steam bath over cooked basil), and to keep insects away (Gams, 1926; Dalziel, 1937). The mucilaginous nutlets of basil are used for coughs and in a drink against gonorrhoea and intestinal disturbances (Gams, 1926; Heyne, 1927). Jain & Jain (1973) report that the volatile oil from basil in India is remarkably anthelmintic.
In Ethiopia basil is used in a medicine against malaria (also as an insect repellent) and as a medicine against headache (Herb. FT; Baldrati, 1946).
Extremely variable mixtures of essential oil are recorded from Ocimum basilicum. According to Hegnauer (1966), the variability results from differences between cultivars or chemotypes, which have long been selected for aroma and taste. Moreover data given in the literature for O. basilicum may refer to other Ocimum species, as the nomenclature and the taxonomy of the genus are rather confusing. Commercially four types of Ocimum basilicum oil are distinguished (Hegnauer, 1966):
- (a) The usual oil: containing mainly linalol and methylchavicol and some cineol and eugenol, but no camphor and methylcinnamate;
- (b) Camphor containing oil: containing much camphor and some cineol, linalol, methylchavicol and alpha-penes;
- (c) Oil containing methylcinnamate: containing 15-75% methylcinnamate;
- (d) Eugenol-containing oil: containing 30-80% eugenol.
According to Gams (1926) the content of essential oil is ca 0.02-0.04% of the fresh leaves and inflorescences or ca 1.5% of the dried product. The oil is extracted by steam-distillation.
Rovesti (cited by Hegnauer, 1966) distinguished four chemotypes within Ocimum menthaefolium Hochst. (?? Ocimum basilicum L.) as growing in Eritrea. He considered them to be ecotypes and classified them as follows:
- (a) var. camphorata: contains 23% camphor, 40% estragol (= methylchavicol), 13% cineol, 10% alpha-penes;
- (b) var. estragolata: contains some lemon oil, 9% linalol, 5% anethol, 73% estragol;
- (c) var. anisata: contains 10% lemon oil, 9% linalol, 39% anethol, 31% estragol;
- (d) var. citrata: contains 9% lemon oil, 10% geraniol, 56% citral and 20% estragol.